Lords of Creation — Eando Binder

The 50th Century men crowded around the gleaming case in which a young man lay sleeping. Suddenly, a terrifying mechanism began to revolve, tremble... Vials of liquid frother, crimsoned, gathered in a hypodermic that jabbed itself into the sleaper's chest. The case shattered; the body stirred... The ultimate miracle had occurred -- as eyes of the 50th Century looked into those of the 20th! But Homer Ellory, alienated young scientist, didn't realize what a devastating battle of wits and science awaited him!