Amoeba — Piers Anthony

Follow Tod Timmonds as he leaves his mundane life behind and embarks on a remarkable trail of adventure and uncertainly.  As Tod navigates the trail he encounters a mix of creatures from alternate realities, periods in time, and different planets.  There are qualities previously hidden in Tod that he must quickly realize to have a chance to survive even one day on his new path.  In short order Tod must differentiate friends from foes, lust from love, and fantasy from reality in order to save the one thing that connects us all before it is too late!