For every situation there are two realms of possibility: Columbus did/did not discover America; the North/South won the Civil War. That is the intriguing premise of this highly unusual adventure y one of the most distinguished authors of science fiction.

When Bill Franklin's father disappears suddenly, Bill faces the challenge of seeking out this fascinating world of duality. Mr. Franklin, a scientist, has apparently set off to prove his theory that the "infinite worlds of maybe" do indeed exist; he leaves behind only some jumbled notes, a box-like machine, and spacesuits. From these, Bill and his physics professor eventually are able to project themselves into a series of astonishing new worlds where they are confronted by terrifying dangers. The end to this fascinating search comes with the revelation of an important discovery that is to have lasting implications in all of their lives.

Lester Del Rey's strongly written adventure will appeal to all who enjoy fine science fiction.