Lost Cosmonauts

Recently I have started reading more about the Soviets' space program and it would seem that they were more than a little cavalier with the lives of their Cosmonauts.  It is widely accepted that Yuri Gagarin was the first man in space but some space historians claim that Gagarin was the first man to make it back safely and that the Soviets lost a number of cosmonauts prior to Gagarin's successful flight.