A.W. Brian Simpson has been variously described by his students as "hysterical", "remarkably in touch" and "so awesome my soul bleeds when I think about him".
He was a noted academic lawyer who specialised in the historical development of law and legal institutions, legal philosophy, the European Convention and human rights.
Professor Simpson was born on 17 August 1931 and served in the British Army as an officer in the Nigeria Regiment of the Royal West African Frontier Force before going to the University of Oxford to study law.
He remained at the university as tutor and Fellow of Lincoln College until 1973.
While at Oxford, Professor Simpson also served as dean of the Faculty of Law at the University of Ghana.
He went on to the University of Kent, where he became a professor and later dean, and then, in 1984, moved to the University of Chicago Law School.
Professor Simpson was hired by the University of Michigan in 1987, where he was to remain until his retirement in 2009, becoming the emeritus Charles F. and Edith J. Clyne professor of law. After his retirement, he moved back to the UK and accepted a visiting chair at the University of Bristol.
He was elected a Fellow of the British Academy in 1983, and Fellow of the American Academy of Arts and Sciences in 1993.
Christopher McCrudden, professor of human rights law at Oxford, paid tribute to a "much-loved" colleague.
"His scholarship remains and is an important consolation, but there is so much more to be remembered: a deeply committed scholar who wore his learning lightly, someone tolerant of all human foibles except pomposity, self-deprecatingly witty, excellent company, a natural storyteller, a loyal friend, an inspirational teacher, a part-time pilot and an intrepid (if somewhat haphazard) sailor who loved messing about in boats," he said.
Evan Caminker, dean of the Law School at Michigan, said that Professor Simpson would be missed by his colleagues, but that he would be missed equally by his students, who were moved to set up a Facebook page in his honour.
"Few professors have commanded the affection of students more completely or more naturally than Professor Simpson," Professor Caminker said.
Professor Simpson died on 10 January 2011. He is survived by his wife Caroline, five children, 12 grandchildren and five great-grandchildren.