Rupert Allan Willis, the elder of two sons of Benjamin James Willis, a banker, was born on 24 December 1898 at Yarram, Victoria, Australia. His mother, Mary Elizabeth Giles (née James), was the daughter of a congregational minister, and his younger brother, James Hamlyn Willis, was a well-known botanist. Rupert Willis's early education was at Yarram State School and he then secured a State scholarship to Melbourne High School before entering Melbourne University in 1917. He graduated from the Alfred Hospital in 1922 and was resident medical officer there for a year before being appointed medical superintendent of the Austin Hospital, Melbourne, where he was subsequently pathologist from 1930 to 1945. During that appointment he spent one year as a Rockefeller research fellow, 1933-34, with Sir Arthur Keith at the Buckston Browne Farm. He returned to England in 1945 and spent three years as Sir William Collins Professor of Pathology at the Royal College of Surgeons. After publication of his two classic works, *The spread of tumours in the human body* (1934) and *Pathology of tumours* (1948), it is not surprising that he sought other opportunities to fulfil himself. In 1948 he was appointed as pathologist at the Royal Cancer Hospital but two years later was invited to take the chair of pathology at Leeds University, where he stayed for five years before being compelled to resign due to ill-health. At that time he developed obstructive jaundice which was attributed to carcinoma of the pancreas. Happily, that diagnosis was to be proved wrong as evinced by his subsequent twenty-five years survival. However this illness led to his premature 'retirement', first to Cornwall and later, after his wife's death, to his daughter's home in Cheshire, where he continued his work on experimental pathology and produced new editions and revisions of his textbooks. He also produced new works on the tumours of children and developmental disorders, as well as a textbook for undergraduates. Moreover, as consultant pathologist to the Imperial Cancer Research Fund he set up the Tumour Reference Collection which was later housed in the pathology department at Leeds. It is hard to exaggerate Rupert Willis's contribution to modern thinking on the pathology of tumours. His deep understanding of human embryology and morphology and an interest in comparative pathology, combined with his detailed observation and documentation, enabled him to lay new foundations for the approach to the classification and histogenesis of tumours. His clearly expressed, sometimes dogmatic, and even uncompromising views on tumour pathology provoked spirited discussion and thought. He certainly had a profound influence on a generation of histopathologists. Outside his professional work he had interests in music, art, philately, geology, petrology, botany, Chinese pottery and porcelain, and wildlife. He was, indeed, a man of the widest culture. His frank and unassuming manner was combined with great personal charm which endeared him to everyone, children and young people having an especial affection for him. In 1924 he married Margaret Tolhurst (well-known for her biography of Baron von Mueller) who was his devoted companion and assistant until her death in 1962. Their son, Dr Allan Trevor Willis, MD Melbourne, became director of the Public Health Laboratory at Luton in 1967, and their daughter, Betty Jean Willis, is a musician. Willis died at the age of 81, on 26 March 1980, survived by his children.