SET THIS HOUSE IN ORDER

A Romance of Souls

By Matt Ruff

HarperCollins 479 pp. $25.95

Matt Ruff's Set This House in Order is a charming though ultimately frustrating novel about multiple personality disorder, child abuse and murder. To Ruff's great credit, this book isn't some morose litany of woes. In fact, it's pretty lighthearted, and obviously a great deal of imaginative flourish went into its conception.

Andy Gage was raised by a seemingly angelic mother and a stepfather whose only hobbies were drinking and torturing his stepchild. This has had a pretty noticeable effect on Andy: He has developed multiple personality disorder. By the age of 29, there are hundreds of "souls," as the personalities are called, roaming around inside Andy; the one in charge now is named Andrew. The other souls spend their time in the rich geography of Andy's mind, a place that includes a lake, an island in that lake named Coventry, a pumpkin patch and a large house where every soul has his or her own room.

At the start of the novel, Andrew loses one job but is offered another by Julie Sivik, a woman who's starting a virtual reality company. She believes that Andrew's MPD is a real-world equivalent of what she hopes to create and market to the public: a rich territory into which anyone can escape. Julie wants Andrew around so she can pick his brain, so to speak.

Julie soon brings in another employee, a woman named Penny Driver. Penny seems awkward, suffers violent mood swings and can't seem to keep track of what she's done even minutes before. Andrew recognizes the symptoms. She doesn't know it, but Penny is a multiple, too.

With the primary characters introduced, the story becomes a kind of quest, with most of the missions leading to Penny's interior. While Andy has created a complex but serviceable method of dealing with his disorder, Penny is still at the mercy of hers. Andrew decides which of the many souls gets to be in charge of Andy Gage's body and for how long. Will it be Aunt Sam, the lovelorn old woman, or Jack, the 5-year-old child? But for Penny, the process isn't genteel. Each personality essentially kidnaps her consciousness for a time. It may be Maledicta, a foul-mouthed hooligan, or Thread, a brainy computer expert. But usually it's Mouse, a frail young woman too afraid of the world to do much of anything.

Therapy often plays a large part in a novel about mental illness, and here it's used both seriously and to comic effect. "There was Dr. Minor, who believed that most MPD cases were the result, not of ordinary child abuse, but of ritual abuse perpetrated by a nationwide conspiracy of Satanic cults. There was Dr. Bruno, who was into past-life regression. There was Dr. Whitney, who as a sideline to his regular practice ran a support group for people who had been sexually assaulted by extraterrestrials. And then there was Dr. Leopold, who recommended litigation as an adjunct to psychotherapy."

But the talking cure also leads to this novel's real downfall, which is that everyone's always explaining. Andrew narrates the mechanics of switching between personalities in his daily routine, and we watch with great interest, but then he goes out for a drink with Julie and essentially tells much of it again. Julie hasn't heard all this, but the reader certainly has. This rehashing of plot points, or ideas, occurs constantly.

The most exciting parts of Andy's life all happened before Andrew took over the body (years of blacking out; battles between Aaron and Gideon, the two primary souls; the creation of Andy's inner geography). So we learn about all of it through tedious conversations between Aaron and Andrew. The retrospective nature of these chats gives us the information but none of the excitement.

For this reason, Penny Driver is the true star of Set This House in Order. We don't know if she's going to be able to control her damaged mind, so her journey is fraught with peril and energy. When she forces herself to confront the frightening mysteries of her past, the reader is hopeful and scared simultaneously. Ruff does right by her, making Penny's story truly dramatic. Andrew's, on the other hand, is pretty bland. His half of the book is tepid, but Penny Driver's is wildfire. *

Victor LaValle is the author of "slapboxing with jesus" and "The Ecstatic."