Scottish pathologist whose Morbid Anatomy of Some of the Most Important Parts of the Human Body (1793) was the first publication in English on pathology as a separate subject and the first systematic study of pathology ever made.

A nephew of the great anatomists John and William Hunter, Baillie was educated at Oxford (M.D., 1789) and soon after became a fellow of the Royal College of Physicians and of the Royal Society. After the publication of his book, he devoted himself to his medical practice, which by 1800 was the largest in London.