Willan, a Yorkshire Quaker, studied medicine at Edinburgh, from where he graduated in 1780. Serving for a short period as physician to the Public Dispensary in Carey Street, London, he left the post for private practice. Among his students were Richard Bright and Thomas Addison. One of the founders of modern dermatology, Willan classified cutaneous diseases according to their appearance. He proposed eight categories, which he called: papular, squamous, exanthematous, bullous, vesicular, pustular, tubercular, and macular. For this system of classification, the Medical Society of London awarded him the Fothergillian Gold Medal in 1790. Willan's work laid the foundation stone of modern dermatology. He was the first to describe several diseases, including impetigo, lupus, psoriasis (also known as 'Willan's syndrome'), sceloderma, ichthyosis, sycosis, and pemphigus. Willan, an early supporter of Edward Jenner, published On vaccine inoculation in 1806, in which he advocated compulsory vaccination. On cutaneous diseases, published serially in four parts between 1798 and 1808, was the first volume of what was to have been a multi-volume definitive work on dermatological diseases. But Willan died shortly after the publication of vol. 1, which covered the first four categories of his classification. His student, Thomas Bateman, continued his work, publishing Delineations of cutaneous diseases in 1817, which included some of the plates which Willan had been unable to use. Willan's book contains thirty-four colour-printed stipple engraved plates, drawn by Willan, Sydenham Edwards, William T. Strutt, W. Darton, Cruickshanks, and Kirtland, and engraved by L. Saillier, Perry and Kirtland. The artists succeeded in producing beautiful illustrations of an unattractive subject.