Best surgeons in Turkey: TOP 300 doctors

Education and Specialization

• 1983 – 1989: Ankara University Faculty of Medicine – Medical Education
• 1990 – 1994: Ankara Numune Training and Research Hospital – General Surgery – Specialization
• 1995 – 2005: Ankara Abdurrahman Yurtaslan Oncology Training and Research Hospital – Specialization
• 2005: Associate Professorship, Ankara Numune Training and Research Hospital
• 2019: Professorship, İstinye University Faculty of Medicine, Department of General Surgery

Experience

• 1989 - 1990: Ardanuç Central Health Center, Artvin – General Practitioner
• 1990 - 1995: Ankara Numune Training and Research Hospital, 2nd Surgery Clinic – Assistant
• 1995 - 1998: Ankara Oncology Training and Research Hospital – Specialist
• 1995 - 1996: 600-Bed Air Force Hospital, Güzelyalı, İzmir – Medical Second Lieutenant
• 1998 - 2005: Ankara Numune Training and Research Hospital, 3rd Surgery Clinic – Specialist
• Sep - Dec 2002: University of Pittsburgh Medical Center, Presbyterian University Hospital, Pittsburgh, PA, USA – Division of Hepatobiliary and Liver Transplantation
• 2002 - 2005: Ankara Numune Training and Research Hospital, 3rd Surgery Clinic – Specialist
• 2005: Associate Professor, Ankara Numune Training and Research Hospital, 3rd Surgery Clinic
• 2005 - 2006: Deputy Chief, Ankara Training and Research Hospital, 4th Surgery Clinic
• 2006 - 2008: Deputy Chief, Ankara Numune Training and Research Hospital, 7th Surgery Clinic
• 2009 - 2012: Chief of Clinic, Kocaeli Derince Training and Research Hospital, General Surgery Clinic
• 2012 - 2019: Chief of Clinic, Antalya Training and Research Hospital, General Surgery Clinic

International Experience

• 2002: University of Pittsburgh Medical Center, Presbyterian University Hospital, Pittsburgh, PA, USA – Division of Hepatobiliary and Liver Transplantation
  • Project Supervisor: De Novo Breast Cancer in Patients with Liver Transplantation
• 2005: Laparoscopic Gastric Band Training, Austria
• 2010: Laparoscopic Lower Gastrointestinal Surgery Training, Cushieri Skill Center, Scotland

Dr. Yahya Özel is a highly experienced general surgeon with expertise in bariatric surgery, hepatobiliary diseases, abdominal hernias, endocrine surgery, and oncological surgery. He completed his medical education at Istanbul University, Istanbul Faculty of Medicine in 1990 and pursued his specialization in General Surgery at Haydarpaşa Numune Training and Research Hospital between 2001 and 2006. His commitment to advanced surgical techniques led him to further training at Tokyo University Hospital, Japan, in the Hepato-Biliary-Pancreatic Surgery and Artificial Organ Division under renowned experts M. Makuuchi and N. Kokudo.

Throughout his career, Dr. Özel has worked at prestigious institutions, including Istanbul University Faculty of Medicine, Haydarpaşa Numune Training and Research Hospital, and Ümraniye Training and Research Hospital. His extensive experience includes roles in ERCP and surgical endoscopy, as well as advanced laparoscopic and robotic surgery. In addition to his clinical practice, he has served as an academic faculty member at Doğuş University, contributing to the education and training of future medical professionals.

Dr. Özel holds several certifications in surgical endoscopy, including the Turkish Surgical Proficiency Certificate. His dedication to minimally invasive surgical techniques, obesity treatment, and hepatobiliary surgery has made him a sought-after specialist in his field. With a career spanning over three decades, he continues to provide high-quality, patient-centered surgical care, ensuring the best outcomes through his expertise and innovative approach.

Education and Expertise

Istanbul University, Istanbul Faculty of Medicine

Istanbul University, Cerrahpaşa Faculty of Medicine

Northwestern University, Transplantation Center

Dr. Lütfi Kırdar Kartal Training and Research Hospital

Bezmialem Faculty of Medicine, Department of General Surgery

Experience

1992 to 1997 – Research Assistant at Istanbul University, Cerrahpaşa Faculty of Medicine, Department of General Surgery

1998 to 2002 – Fellow at Northwestern University, Transplantation Unit

2003 to 2008 – Chief Assistant at Kartal Training and Research Hospital

2008 to 2011 – Associate Professor at Kartal Training and Research Hospital

2011 to 2013 – Associate Professor at Bezmialem University Faculty of Medicine, Department of General Surgery

2013 to 2018 – Associate Professor at Kartal Training and Research Hospital


Professional Memberships

-Deutsche Gesellschaft Für Chirurgie

-American Society for Transplantation

-Breast Surgery Association

-Trauma Association

-Hepatobiliary Surgery Association

-Colorectal Surgery Association

Education

Medical Doctor Education: Maltepe University Faculty of Medicine, 2008, Istanbul/Turkey
General Surgery Residency: Istanbul University Faculty of Medicine, 2018, Istanbul/Turkey

Experience

Tokat Erba State Hospital, 2008-2012, Tokat/Turkey
Istanbul University Faculty of Medicine, 2012-2018, Istanbul/Turkey
Ağrı Doğubeyazıt State Hospital, 2018-2020, Ağrı/Turkey

Scientific Memberships

Turkish Medical Association
Turkish Hepatobiliary Surgery Association
Trauma and Emergency Surgery Association
Turkish Surgical Association

SUB-SPECIALISTS 

• *Trauma Surgery 
• *Joint Prosthesis Surgery
• *Knee Surgery 
• *Arthroscopic Surgery 
• *Spine Surgery 
• *Deformity Surgery 

TECHNOLOGIES 

• *Robotic Joint Replacement Systems 
• *Kinematic Approach of Knee Replacement Surgery 
• *Journey II Knee Prosthesis System

EDUCATIONAL INFORMATION 

1. *Eskişehir Osmangazi University Faculty of Medicine (Bachelor’s Degree, 2005-2011) 
2. *Health Sciences University Ankara Education and Research Hospital (Specilization Education, 2012-2017) 
3. His international published article is named as ‘’Mahmuti, A., Güler, U.O., Haberal, B., Şimşek, E.K., Yüksel, S., Temiz, A., Tuncay, I.C. Biomechanical Comparison of Polymethylmethacrylate Augmentation Methods in Failed Pedical Screw Revision. Turk Neurosurg. 2021; 31 (5): 788-794. DOI: 10.5137/1019-5149.JTN.34653-21.2. PMID: 34374983’’. 

COURSES INFORMATION

1. *11th TOTBID School of Basic Sciences and Research, Malatya. 
2. *1-3 March 2013. AO Basic Trauma Course (Principles in Operative Fracture Management), İstanbul 2013. 
3. *10th Basic Orthopedic Trauma Education Meeting, Ankara. 13-14 September 2013. 
4. *6th Intramedullary Nailing Course, İzmir 2013. 
5. *Instrumentation Course in Arthroscopic Surgery, İstanbul 2013. 
6. *6th Minimally Invasive, Locked Plate Osteosynthesis and Advanced Trauma Education Meeting. 5-6 December 2014. 
7. *TOTBID GKD-PEV Course, Konya 2015.
8. *AO Advanced Trauma Course (Principles in Operative Fracture Management), Ankara 2017. 
9. *Stryker Mako Certification Lab., Amsterdam. June 2019.

CONGRESS INFORMATION

1. *23rd National Turkish Orthopedics and Traumatology Congress. 29 October – 3 November 2013. 
2. *5th Orthopedics and Traumatology İstanbul Meeting. 10-12 April 2015. 
3. *Spine Intervention Society 2019 European Congress, Munich. May 2019. 

CAREER INFORMATION

1. *Şırnak İdil State Hospital (General Practitioner, 2017-2019) 
2. *Ankara Education and Research Hospital (Specialization Education, 2012-2017) 
3. *Şırnak State Hospital (Specialist Doctor, 2017-2019) 
4. *Turan Turan Health Group (OM Spine Surgery Center – Robotic TT Orthopedics Robotic Surgery Center) (Specialist Doctor, 2019-now) 
5. *Başkent University Faculty of Medicine Orthopedics and Traumatology Department Adana Dr. Turgut NOYAN Application and Research Center (Specialist Doctor, 2020-2021)

Dr. Haluk Talu is an experienced Eye Diseases Specialist with 19 years in the field. He has performed over 20,000 surgeries. He provides general eye exams and treats cataracts with IOL replacement. He also performs LASIK, ReLEx SMILE, and presbyopia treatments.

Dr. Talu has written more than 50 scientific articles. He is a member of the Turkish Society of Ophthalmology and the American Society of Cataract and Refractive Surgeons. He is dedicated to advancing eye care and maintaining high professional standards.

Education

Istanbul University Istanbul Faculty of Medicine, Department of General Surgery, May 2007
Istanbul University Istanbul Faculty of Medicine, July 2001

Experience

2007-2008 Şırnak Military Hospital
2008-2009 Bağcılar Training and Research Hospital
2010-2011 Istanbul Faculty of Medicine Organ Transplantation
2011-2012 Başkent University Organ Transplantation
2013-2017 Erciyes Universityniversity Organ Transplant
2017-2019 Bilim University FNH Organ Transplant
2019-2020 Yeditepe University Organ Transplant
2020-2023 Biruni University Medicana Hospital Organ Transplant

Scientific Memberships

Istanbul Medical Chamber
Turkish Surgical Association
Turkish Hepatopancreatobiliary Surgery Association
ILTS

​Dr. Azer Zeynalov is a plastic, reconstructive, and aesthetic surgeon based in Istanbul, Turkey, with over 12 years of experience in the field.

Experience

• 2020

Istanbul Medipol University General Surgery Clinic

• 2019 - 2019

TURKISH COLON AND RECTUM SURGERY SOCIETY

• 2018 - 2018

İNÖNÜ UNIVERSITY

• 2018 - 2018

TURKISH OSTOMY SURGERY SOCIETY

• 2018

MALATYA GASTROINTESTINAL SURGERY SOCIETY

• 2009 - 2009

DR.LÜTFİ KIRDAR EDUCATION AND RESEARCH HOSPITAL

• 2009 - 2009

10th NATIONAL BREAST DISEASES CONGRESS

• 2008 - 2008

TURKISH SURGICAL ASSOCIATION

• 2006 - 2012

Kartal Training and Research Hospital, General Surgery Assistant

Education 

• 2012

ISTANBUL KARTAL DR.LÜTFİ KIRDAR TRAINING AND RESEARCH HOSPITAL, GENERAL SURGERY

• 2003

KARADENIZ TECHNICAL UNIVERSITY, FACULTY OF MEDICINE

2023 – Istanbul Gaziosmanpaşa Taksim Education and Research Hospital – General Surgery Clinic Associate Professor

2013 – Istanbul Gaziosmanpaşa Taksim Education and Research Hospital – General Surgery Clinic Specialist

2008 – 2013 Private Medical Park Fatih Hospital, General Surgery Specialist - Deputy Chief Physician

2005 – 2007 Private Gelişim Hospital – General Surgery Specialist

2003 – 2005 Private Istanbul Şafak Hospital – General Surgery Specialist - Chief Physician

2002 – 2003 ISTANBUL HASEKİ EDUCATION AND RESEARCH HOSPITAL – General Surgery Clinic Assistant Physician

1998 – 2002 Ankara Education and Research Hospital – General Surgery Clinic Assistant Physician

1998 – Health Sciences University – Istanbul Haseki Health Application and Research Center – Medical Specialization

1991 – Gazi University Faculty of Medicine – Bachelor’s Degree

Certificates

IGM Diagnosis, Treatment Workshop, Granulomatous Mastitis, Kocaeli, Certificate, 07.10.2023 (National)

ibreast 51- Free Flap Reconstruction, Breast Cancer Surgery, Online, Certificate, 30.09.2023 – 30.09.2023 (International)

ibreast 50- Triple Negative Breast Cancer, Breast Cancer, Online, Certificate, 02.09.2023 -02.09.2023 (International)

ibreast 49- Implant Based Reconstruction, Breast Cancer, Online, Certificate, 12.08.2023 -12.08.2023 (International)

ibreast 48- DCIS, İbreast 48- DCIS, Online, Certificate, 15.07.2023 -15.07.2023 (International)

ibreast 47- Conference Updates, Breast Cancer, Online, Certificate, 25.06.2023 -25.06.2023 (International)

ibreast 46- Margin Revisited, Breast Cancer, Online, Certificate, 10.06.2023 -10.06.2023 (International)

1. International 4. National Breast Surgery Congress, Breast Surgery, Ürgüp, Certificate, 05.05.2023 – 07.05.2023 (International)

ibreast 44- HER2 Positive Disease, Breast Cancer, Online, Certificate, 29.04.2023 -29.04.2023 (International)

St-Gallen 2023, St-Gallen Congress Summary Meeting, Istanbul, Certificate, 01.04.2023 -01.04.2023 (National)

ibreast 43- Save The Nipple, Breast Cancer, Online, Certificate, 25.03.2023 -25.03.2023 (International)

ibreast 42-Chest Wall Perforator Flap Revisited, Breast Cancer, Online, Certificate, 25.02.2023 -25.02.2023 (International)

ibreast 41- High Risk And B3 Lesions, Breast Diseases, Online, Certificate, 28.01.2023 -28.01.2023 (International)

15. New Approaches in Breast Cancer Education Meeting, Breast Cancer, Istanbul, Certificate, 07.01.2023 – 08.01.2023 (National)

Articles she wrote and took part in;

1.YILDIRIM EMİNE, BEKTAŞ SİBEL, YETİŞ FIRAT, YILDIZ EREN OZAN, ÖZDEMİR MUHAMMED, KOMUT NESLİHAN, ÇALIK MUSTAFA, ER AHMET MUZAFFER. Correlation between breast and axillary pathologic complete response after neoadjuvant chemotherapy in breast cancer. Annali Italiani di Chirurgia, 2023

2.UZUN NEDİM, YILDIRIM EMİNE. Relationship Between Toilet Type and Hemorrhoids. Bezmialem Vakif University, 2022

3.YILDIZ EREN OZAN, YILDIRIM EMİNE, ORHUN ERDOĞAN KIVILCIM, ERYILMAZ İKLİL, YÜNLÜEL EMİR MEHMET, YETİŞ FIRAT, ULUKENT SUAT CAN. The effect of the covid 19 pandemic on the number of patients treated for acute and complex acute appendicitis. Annali Italiani di Chirurgia, 2202

4.YILDIRIM EMİNE, BEKTAŞ SİBEL, ÖZDEMİR MUHAMMED, KARAGÜLLE AHENK, ER AHMET MUZAFFER, UÇAR NEŞE. Upgrade Rates of DCIS, Intraductal Papilloma, and the Other High-risk Breast Lesions. Hamidiye Medical Journal, 2022
 

5.ÖZKAN GÜMÜŞKAYA PERİHAN, ALTUN ÖZGÜR, KARAKÜTÜK YÜZTAŞ NUR, ÖZSOY NESLİHAN, AYDIN TUTAK GÜLTEN, YILDIRIM EMİNE, ADAŞ MİNE, KÜÇÜK MEHMET. COVID-19 Pnömonisi Sonrası AntiHBs Değerlerindeki Değişiklikler. Journal of Contemporary Medicine, 2022;12(4), 

6.KOMUT NESLİHAN, BEKTAŞ SİBEL, YILDIRIM EMİNE. The relationship of tumor budding with GOLPH3 expression and histopathological prognostic parameters in colorectal adenocarcinoma. Annals of Diagnostic Pathology 2022 Jun;58:151933. 

7.KAYADİBİ YASEMİN, UÇAR NEŞE, AKAN YEŞİM NAMDAR, KAYA MEHMET FATİH, YILDIRIM EMİNE, ALADAĞ KURT SEDA, SOYLU BOY FATMA NUR, TAŞKIN FÜSUN, İÇTEN GÜL ESEN. Magnetic resonance imaging findings associated with recurrence in idiopathic granulomatous mastitis. Clinical Imaging, 2022

8.YILDIRIM EMİNE, KEĞİN MURAT, ÖZDEMİR MUHAMMED, BEKTAŞ SİBEL, PELEN ZEKERİYA, ER AHMET MUZAFFER. Neoplasms of theAppendix; Single Institution and Ten-Year Experiences Results. Turkish Journal of Trauma and Emergency Surgery, 2022;28(3), 352-360

9.YILDIRIM EMİNE, YILDIZ EREN OZAN, ERYILMAZ İKLİL, ER AHMET MUZAFFER, BEKTAŞ SİBEL. Comparison of excised breast volume, re-excision rate and margin positivity in breast-conserving surgery in breast cancer patients using and not using neoadjuvant chemotherapy. Journal of Surgery in Medicine,2022;6

10.YILDIRIM EMİNE, BEKTAŞ SİBEL, PELEN ZEKERİYA, YANIK İREM, ER AHMET MUZAFFER, ÇENGEL FERHAT, ÖZKAN GÜMÜŞKAYA PERİHAN. Histopathological, Radiological, and Demographic Factors Predicting the Response to Neoadjuvant Therapy for Rectal Cancer. Journal of Gastrointestinal Cancer, 2022;53(1)

11.KAYADİBİ YASEMİN, KOÇAK BURAK, UÇAR NEŞE, AKAN YEŞİM NAMDAR, YILDIRIM EMİNE, BEKTAŞ SİBEL. MRI Radiomics of Breast Cancer: Machine Learning-Based Prediction of Lymphovascular Invasion Status. Academic Radiology, 2022;29(1), 126-134.

12.YILDIRIM EMİNE, UÇAR NEŞE, YETİŞ FIRAT, KAYADİBİ YASEMİN, BEKTAŞ SİBEL. Diagnostic performance of breast imaging with ultrasonography, magnetic resonance and mammography in the assessment of residual tumor after neoadjuvant chemotherapy in breast cancer patients. Journal of Surgery and Medicine, 2022;6(1), 43-48

13.YILDIRIM EMİNE, BEKTAŞ SİBEL, GÖKTAŞ AYDIN SABİN, ER AHMET MUZAFFER, YANIK İREM, ÖZKAN GÜMÜŞKAYA PERİHAN, YILMAZ BARBAROS UTKU, BİLİCİ AHMET, ÖNCEL MUSTAFA. Factors Predicting Response to Neoadjuvant Chemotherapy in Locally Advanced Gastric Cancer. Journal of Istanbul Faculty of Medicine / İstanbul Tıp Fakültesi Dergisi, 2022;85(1), 41-50. 

14.YILDIRIM EMİNE, Pelen Zekeriya, KEĞİN MURAT, UÇAR NEŞE, KAYADİBİ YASEMİN, GÜNDOĞAR ÖZGECAN. Evaluation of the Reliability of Preoperative Ultrasonography and Ultrasonography-Guided Fine Needle Aspiration Biopsy in Axillary Staging in Patients With Breast Cancer. Journal of Academic Research in Medicine, 2021;11(3), 269-276., 

15. KAYADİBİ YASEMİN, UÇAR NEŞE, KAYA MEHMET FATİH, YILDIRIM EMİNE, BEKTAŞ SİBEL. Characterization of Suspicious Microcalcifications on Mammography Using 2D Shear-Wave Elastography. Ultrasound in Medicine & Biology, 2022;47(9), 2532-2542. 

16.KAYADİBİ YASEMİN, TEKCAN ŞANLI DENİZ ESİN, UÇAR NEŞE, YILDIRIM EMİNE, ŞANLI AHMET NECATİ. Evaluation of the Appearance Characteristics of Suspicious Microcalcifications Detected by Ultrasonography. Journal of Academic Research in Medicine, 2022;11(2), 199-205. 

17.YILDIRIM EMİNE, ÖZER HİLAL, ÖZER İLTER, KOYUNCU ADİL, YILDIRIM TİMUR. The Effects on Bacterial Translocation and Tissue Damage of Selenium Treatment in an Experimental Intestinal Ischaemia-Reperfusion Model. Turkish Journal of Trauma and Emergency Surgery, 2021;27(4), 389-394. 

18.YILDIRIM EMİNE, AKBAŞ PELİN, ORHUN ERDOĞAN KIVILCIM, BEKTAŞ SİBEL, ÖZKAN GÜMÜŞKAYA PERİHAN, ER AHMET MUZAFFER, PALTURA CEKİ. The comparison of the histopathological results of the thyroid fine-needle aspiration biopsies in the 795 patients with thyroidectomy. Diagnostic Cytopathology, 2021

Prof. Dr. Alper Agca is an experienced ophthalmologist. He specializes in ReLEx SMILE, LASIK, LASEK, laser eye surgeries, and cataract surgery with multifocal lens implants. He has performed over 15,000 surgeries. Dr. Agca is known for his skill and excellent results in refractive and cataract procedures.

He is a member of the Turkish Ophthalmological Association. He also served as a board member of the Society of Cataract and Refractive Surgery from 2019 to 2020. In 2014, he won second place for Best Poster at the XXXII Congress of the ESCRS. This award highlights his contributions to ophthalmology research and practice.

Dr. Huseyin Sinan is a board-certified General Surgeon. He specializes in metabolic and morbid obesity surgery. He has advanced skills in minimally invasive surgical techniques. Dr. Sinan has served in both military and civilian healthcare. He has held positions such as Chief Physician and faculty member. He completed his medical degree and general surgery residency at Gülhane Military Medical Academy. He also completed a fellowship in Advanced Laparoscopic Surgery at the University of Washington.

Dr. Sinan’s clinical interests include metabolic surgery, obesity management, and type 2 diabetes. He also focuses on ileal interposition and transit bipartition procedures. He is a member of the Turkish Surgical Society and the International Federation for the Surgery of Obesity and Metabolic Disorders (IFSO). These memberships show his commitment to professional excellence in surgery.

2023 - Present, Istanbul/Türkiye

MEMORIAL SISLI HOSPITAL

Pediatric Surgery Specialist

2016 - 2023, Kocaeli/Türkiye

PRIVATE GULF MARMARA HOSPITAL

Pediatric Surgery Specialist

2011 - 2016, Tokat / Türkiye

GAZİOSMANPAŞA UNIVERSITY MEDICAL HOSPITAL

Assist. Prof. Dr. Department of Pediatric Surgery

2010 - 2011, Trabzon / Türkiye

TRABZON NUMNE TRAINING AND RESEARCH HOSPITAL

Pediatric Surgery Specialist

2006 - 2011, Nigde/Türkiye

NİĞDE DR.DOĞAN BARAN WOMEN AND CHILDREN HOSPITAL PEDIATRIC SURGERY SPECIALIST

Pediatric Surgery Specialist

1998 - 2001, Ordu/Türkiye

ORDU GURGENTEPE STATE HOSPITAL

Emergency room

2020 - Present, Istanbul/Istanbul/Türkiye

MEMORIAL ATASEHIR HOSPITAL

Thoracic Surgery Specialist

2018 - 2020, Tekirdağ/Tekirdağ/Türkiye

CORLU STATE HOSPITAL

Thoracic Surgery Specialist

2012 - 2018, Istanbul/Istanbul/Türkiye

MARMARA UNIVERSITY FACULTY OF MEDICINE

Research Assistant

2011 - 2012, Bilecik/Bilecik/Türkiye

BILECIK GOLPAZARI STATE HOSPITAL

Chief Physician

2010 - 2012, Bilecik/Bilecik/Türkiye

BILECIK GOLPAZARI STATE HOSPITAL

General Practitioner

Dr. Yavuz Kamil Bardak is an experienced ophthalmologist. He has performed over 35,000 surgeries. His main areas are cataract surgery with IOL replacement, glaucoma management, and retinal treatments. He is also skilled in general eye exams and advanced retinal procedures.

Dr. Bardak has published many research papers in national and international journals. He has received several awards, including the Troutman Award and best paper and poster recognitions. He completed his medical degree at Hacettepe University. He received further ophthalmology training at Ankara University and the University of Nijmegen in the Netherlands.

Dr. Aylin Koc Akbay is an experienced ophthalmologist. She focuses on treating complex eye diseases and performing eye surgeries. She is skilled in cataract surgery with IOL replacement, as well as ReLEx SMILE, LASEK, and LASIK procedures. Her work has helped many patients achieve better vision.

Dr. Akbay is a member of respected organizations such as the Turkish Society of Ophthalmology, the American Academy of Ophthalmology, and the European Society of Cataract and Refractive Surgeons. She is known for her expertise and dedication to patient care. Her patients report high satisfaction, and she continues to contribute to advances in ophthalmology.

Prof. Dr. Hamdi Er is a respected Eye Diseases Specialist with a strong background in ophthalmology. He has published 63 international papers and many national articles. His work shows a clear commitment to research and progress in eye care.

Dr. Er has completed over 12,000 surgeries. He specializes in cataract surgery with IOL replacement, LASIK, and retina transplantation. He is a member of organizations such as TOD, ASRS, AAO, and EVRS. These memberships highlight his dedication to professional growth and education in his field.