First of a trilogy inspired by the what-is-reality terrors of Philip K. Dick, from the author of the interminable Well World series (Shadow of the Well of Souls, 1994), etc. When computer-whiz Cory Maddox discovers that the company he thought he part-owned has been sold out from underneath him, he has little choice but to listen to Al Stark of the NSA and his offer of a hush-hush job. Seems that computer genius Matthew Brand (dead? maybe) had found a way to create Sims, or virtual realities, as convincing as reality itself. What Stark needs from Maddox is his state-of-the-art interface. But then Maddox receives an anonymous message: ``Everything you think you know is wrong.'' He begins to have strange visions, and to recall memories of what seem to be past lives. Stark intimates that the Sims are actually other realities, connected by ``rabbit holes''; only a handful of people are really real, the rest are just computer-generated figments. And Stark's ambition is to control the whole system. As the Lewis Carroll references proliferate, the plot whirls off in a paranoid blur. Slick, brisk entertainment engendered by blarney, Alice, and demented solipsism.