If you want to read something incredible about Church, read Rota's reminiscence. It's the first section of https://www34.homepage.villanova.edu/robert.jantzen/princeto....
Related:
Alonzo Church, 92, Theorist of the Limits of Mathematics(1995) - https://news.ycombinator.com/item?id=12240815 - Aug 2016 (1 comment)
Gian-Carlo Rota on Alonzo Church (2008) - https://news.ycombinator.com/item?id=9073466 - Feb 2015 (2 comments)