Endurance: The Life and Times of Emil Zatopek is written by Rick Broadbent through Wisden Sports Writing and comes out on May 24.
http://www.amazon.com/Endurance-Extraordinary-Z%C3%A1topek-Wisden-Writing/dp/1472920228
Today We Die a Little!: The Inimitable Emil Zátopek is written by Richard Askwith and comes out on an unspecified day in May.
http://www.amazon.com/Today-We-Die-Little-Inimitable/dp/1568585497
They look to me to be the first bona fide biographies written on Zatopek, odd that they come out so close to each other. Zatopek is a hero of mine, I'm going to grab a copy of one. Not sure which I'll buy. Just thought it was interesting and that I'd share.