Alan Dean Foster 
Parallelities 

It was just an average day for tabloid reporter Max Parker when he arrived in Malibu for a demonstration of a brand-new parallel-universe machine. But everything changed in an instant when inventor Barrington Boles succeeded in making Max the human gate to numerous parallelities.Now Max was lost in a virtual sea of collateral worlds, confronting man-eating aliens, dinosaurs, talking frogs, dead Maxes, girl Maxes, old Maxes, even ghost Maxes. His only chance to escape the space-time continuum was to find Boles and hole the loony genius could rescue him. But how could he be sure which world was real, which Max was Max, and which Boles was the Boles who could stop the madness – or trap Max in the wrong world forever…?