Split Infinity (Apprentice Adept, Bk. 1)

On the technological, decadent world of Proton, someone was trying to destroy Stile, serf and master Gamesman. His only escape lay in Phaze, a world totally ruled by magic. Soon he learned that his alternate self had already been murdered, and that he was next. On Proton, his fate depended on winning the great Games. On Phaze, he must master magic to survive. And if he used any magic at all, his friends were determined to kill him at once!

Split Infinity is the first book in Piers Anthony's Apprentice Adept series. Here two worlds exist side by side: Proton and Phaze. Proton is a science fiction world, where everything works in a logical and scientific manner. Phaze is a fantasy world similar to Anthony's Xanth in that there's no such thing as science--it's all done with magic! The wild plot involves a young adventurer named Stiles who lives in Proton and learns that his "double" in Phaze has been murdered. To solve his own demise, Stiles must travel between the two realities, each abounding with the expected confusions and unexpected plot twists for which Anthony is famous. An artful blending of SF and fantasy clichés and situations, Split Infinity shows Piers Anthony at the top of his ingenious game(s). --Stanley Wiater