Sir Archibald Edward Garrod was an English physician who pioneered the field of inborn errors of metabolism. He also discovered alkaptonuria, understanding its inheritance. He served as Regius Professor of Medicine at the University of Oxford from 1920 to 1927. Garrod is best known for his scientific study of inborn errors of metabolism. He developed an increasing interest in chemical pathology, and investigated urine chemistry as a reflection of systemic metabolism and disease. This research, combined with the new understanding of Mendelian inheritance, evolved from an investigation of a few families with an obscure and not very dangerous disease (alkaptonuria) to the realization that a whole territory of mysterious diseases might be understood as inherited disorders of metabolism. Working with William Bateson, Garrod came to understand the pattern of alkaptonuria appearance in children based on Mendelian principles. Once he applied Mendel’s concepts to alkaptonuria, he published a paper in 1902 called The Incidence of Alkaptonuria: A Study of Chemical Individuality. In the paper, Garrod explains how he came to understand the condition and speculates as to its causes. He cites various case studies and compares alkaptonuria to albinism in how it is inherited. He summarized his thoughts on the relationship of inheritance to metabolic disease in his book Inborn Errors of Metabolism.