John Coates was Sadleirian Professor of Pure Mathematics at the University of Cambridge from 1986 until 2012. Most of his research has focused on the mysterious, and still largely conjectural, connections between special values of L-functions and purely arithmetic questions, largely via the p-adic techniques of Iwasawa theory. Professor Coates was elected a fellow of the Royal Society of London in 1985, and served as President of the London Mathematical Society from 1988 to 1990. He was awarded the Senior Whitehead Prize by the London Mathematical Society in 1997.