Pudupakkam K. Vedanthan (PK) is the lead editor of the Textbook of Diagnostic and Therapeutic Procedures in Allergy. He is a native of Mysuru, India and a graduate of Government Medical College, University of Mysore. He was awarded the 10th rank in the Pre University Course and distinctions in Physiology, Pharmacology and Pathology. He served as a lecturer in Pathology at his Almamater before moving to USA in 1971. He completed his residency in Pediatrics at Rhode Island Hospital at Brown University and Fellowship in allergy & Immunology at National Asthma Center, Denver, Colorado. He is board certified by the American Boards of Pediatrics and Allergy, Asthma and Immunology. He served for 35 years in Consultation practice in Colorado, as well as maintained academic affiliation with University of Colorado, Denver where he has been a Clinical Professor of Medicine for the past two decades. He has published in both national and international journals and has been active in the academic circle in various capacities. He was the lead editor for the Textbook of Allergy for the clinician published by the CRC Press in 2014 and 2019. He has contributed to Colorado Medical Society (CMS), Association of American Physicians of Indian origin (AAPI) in several capacities. His major contribution has been in Global medicine since he established a medical charity namely ‘International Asthma Services (IAS)’ (www.saahns.org) in 1992. IAS has been active in several developing countries like India, Sri Lanka, Mauritius, Kenya, Russia, Myanmar, Philippines, Argentina, Nepal conducting CMEs for health professionals and Asthma allergy Awareness camps for patients and their families and public in general. IAS has also partnered with major medical institutions in establishing formal PG diploma courses in allergy, asthma and immunology offered at Vellore Tamil Nadu, Delhi, Kolkata, and Bangalore INDIA and Barbados, West Indies. These courses have been sponsored/endorsed by the American Academy, Asthma & Immunology (AAAAI), and the Center for Global Health, College of Preventive Medicine, University of Colorado at Anschutz campus, Aurora, Colorado, USA. Nearly 1500 specialists have been trained under this program. Dr. PK has also been involved in providing voluntary medical care to the refugee population through Colorado Alliance for Health Education & Promotion (CAHEP), Denver, Colorado for the past three decades. He has also recently initiated the PRAANA Charitable Allergy Asthma clinics Initiative to serve the needy and sick in India, Nepal, Kenya and Barbados. In recognition of these activities, IAS was recognized in 2015 by the Centre for Global Health, School of Public Health, University of Colorado with the prestigious award of ‘Excellence in Global health’. He has been the recipient of AAAAI Special recognition award for the year 2021, AMA Leadership award, UCD Distinguished Service award, Rotary ‘Service Above Self Award’, UCD International Faculty award, Special Innovator award from the department of Medicine, University of Colorado, Denver. Harold S. Nelson received an undergraduate degree in economics from Harvard College and later earned a doctor of medicine degree from Emory University. He then completed a residency in internal medicine at Letterman General Hospital and a fellowship in allergy/immunology at the University of Michigan. Dr. Nelson has published over 450 articles and book chapters. He has served on the Board of Regents of the American College of Allergy, Asthma, and Immunology (ACAAI), as well as on the Board of Directors of both the American Academy of Allergy, Asthma, and Immunology (AAAAI) and the American Board of Allergy and Immunology (ABAI). He was a member of the First, Second and Third Expert Panels of the NIH—NAEPP for developing the Guidelines for the Diagnosis and Management of Asthma. Dr. Nelson has been honored with the ‘Fellow Distinguished Award’ and ‘Gold-Headed Cane Award’ by the ACAAI; the ‘Distinguished Clinician Award’ ‘Special Recognition Award’ and ‘Distinguished Service Award’ by the AAAAI; the ‘Outstanding Clinician Award’ from the World Allergy Organization and the ‘Lifetime Achievement Award’ by National Jewish Health. He has also been honored with named 428 Textbook of Allergy for the Clinician lectureships at the annual meetings of the ACAAI 2008–2009, the AAAAI 2001–2013 and the Western Society of Allergy and Immunology 2018–2022. Hugo P.S. Van Bever completed his medical studies at the State University of Ghent, Belgium (1971–1978) and did his training in pediatrics at Children’s Hospital, State University of Ghent, Belgium from 1978–1983. Following that he became Resident in Paediatric Allergy and Pulmonology, University of Antwerp, Belgium from 1984–1993, Associate Professor in Paediatric Allergy and Pulmonology, University of Antwerp, Belgium from 1993–1997 and Professor in Paediatric Allergy and Pulmonology, University of Antwerp, Belgium from 1997. From 1997–2001 Hugo Van Bever was also the Head of the Department of Paediatrics, University of Antwerp, Belgium. He joined the National University Singapore as Professor, Senior Consultant, and Head of Paediatric Allergy and Immunology in the Department of Paediatrics in June 2002. Since 2002 he has been an active member of the Board of The Asian Pacific Academy of Paediatric Allergy, Respirology, and Immunology (APAPARI), in which he was responsible for research and education in pediatric allergy, organizing APAPARI workshops in different Asian countries. From 2019 till May 2021, he was the President of APAPARI. He is also a board member of APAAACI and committee member of the Immunotherapy Working Group of WAO. He has been Associate Editor of The European Respiratory Journal (1993–1998). Currently, he is reviewer for The European Journal of Paediatrics, Pediatrics, Paediatric Allergy and Immunology, Allergy, Paediatric Pulmonology, The European Respiratory Journal, Paediatric Research, British Medical Journal, The American Journal of Respiratory and Critical Care Medicine and Archives Diseases of Childhood. Hugo Van Bever defended his PhD thesis successfully in June 1993 at the University of Antwerp. The title of this thesis is: “Late asthmatic reactions in childhood asthma and Influence of specific immunotherapy upon the late asthmatic reactionˮ. He has published more than 350 papers in national and international journals. His current research is focused on eczema, food allergy, allergic rhinitis, sublingual immunotherapy, and primary prevention of allergy. He runs clinics in NUH on pediatric allergy, especially on asthma, allergic rhinitis, eczema, and food allergy. Mandakolathur R. Murali M.D. received his undergraduate (MBBS) and postgraduate (MD) degrees in Internal Medicine at Stanley Medical College in Chennai, India. He was the recipient of the Government Gold medal, in both the MBBS and MD, as a recognition of being the best outgoing student of Madras University. He completed a residency in Internal Medicine and a fellowship in Allergy and Clinical Immunology as well as the Assistant training program Director in Allergy and Clinical Immunology at SUNY, Downstate Medical Center in Brooklyn, NY. He is boarded in Internal Medicine, Allergy and Clinical Immunology as well as Diagnostic and Laboratory Immunology. He was a full-time faculty in Allergy and Clinical Immunology at SUNY Brooklyn till 1992, and then served as the Director of Allergy Clinic as well as training program Director in Allergy and Immunology at SUNY Stony Brook in N.Y. Since 2002, he is the Director of Clinical Immunology laboratory at Massachusetts General Hospital, serving as full time faculty in departments of Medicine and Pathology, in the division of Rheumatology, Allergy and Clinical Immunology. He holds the rank of an Assistant Professor of Medicine at Harvard Medical School in Boston. Since 1979 he has been involved in teaching clinical and laboratory medicine to medical students, residents and fellows and has been recognized with several teaching awards at all 3 institutions he has served. He is a senior clinician with expertise in allergic and immunologic disorders and autoimmunity. His research interests and publications include immunopathology of autoimmune diseases, complement disorders, immunodeficiency diseases and evaluation of monoclonal gammopathies. He has been a member of the in-training exam committee of the AAAAI for over 25 years. He has contributed to chapters on immunodeficiency diseases, mechanisms of allergic diseases, complement disorders, cryoglobulins as well as evaluation of autoantibodies in systemic autoimmune diseases.