he 1980s marked a decade of transition for Conway. He married a second time, to fellow mathematician Larissa Queen, and left Cambridge for the position of John von Neumann chair of mathematics at Princeton University. It also gave rise to another prolific stretch of his professional career. Following some 15 years of development, the ATLAS of Finite Groups was published in 1985 and became one of the definitive works on group theory. In addition, Conway earned a patent with AT&T mathematician Neil Sloane for applying sphere packing theory to telecommunications.
Conway underwent a difficult period in the early 1990s, marked by another divorce, a heart attack and a suicide attempt. He recovered to pen The Book of Numbers in 1996 with the University of Calgary's Richard Guy, and won a series of awards in the following years. In 2001, he married his third wife, Diana.
Slowed by a stroke in 2006, Conway nevertheless continued his intellectual pursuits. That year he and Princeton colleague Simon B. Kochen published their free will theorem, essentially stating that if people have free will, then elementary particles have free will as well. He also co-authored the book Symmetries of Things (2008), and collaborated on several projects with Alex Ryba of the City University of New York's Queens College.