The books in this trilogy are #1 “Split Infinity”, #2 The Blue Adept and the final “Juxtaposition. Piers Anthony is a mystery to me. I have greatly enjoyed some of his books such as “The Source of Magic” and “If I Pay Thee Not in Gold” with Mercedes Lackey. I just didn’t find any thing to identify with in this trilogy. I didn’t care for the story line or characterizations. I wouldn’t discount him out as an author though. He has written some very entertaining stuff. The Xanth fantasy series had some truly funny books.
Body of work of Piers Anthony
Piers Anthony’s site: http://www.hipiers.com/