Stephen Leeds is perfectly sane. It's his hallucinations who are mad.

A genius of unrivaled aptitude, Stephen can learn any new skill in a matter of hours using hallucinatory people- he calls them aspects- to hold and manifest the information. Wherever he goes, Stephen is joined by a team of imaginary experts. he uses them to solve problems... for a price.

His brain is getting a little crowded, and the aspects tend to take on lives of their own. When a company hires him to recover a stolen camera that can allegedly take pictures of the past, Stephen finds himself on an adventure that may finally give him a vital clue into the true nature of his aspects.
Soft cover.