What if an eminent psychiatrist--in order to get a closer look inside the mind of his showcase psychopathic patient--used a gizmo he'd cooked up at home to introject his own mind into the patient's body, while the patient, finding his own mind transferred to the psychiatrist's body, took off on a rampage? The idea isn't as new as it sounds--apart from the rough Jekyll/Hyde analogy, H.G. Wells published a closely similar story over 50 years ago--but Belletto's juiced it up with some psychological jargon, a 12-cylinder suspense plot, and some shocking misogyny. Michel Zyto, the patient, has a history of sexual violence, and his masquerade as the beloved bourgeois Dr. Marc Lecroix is punctuated by his violent fantasies concerning Marc's inoffensive wife Marie (who's pleased by the renewed attention she's getting from her erstwhile indifferent husband) and Marc's mistress, actress Marianne Matys (who continues to enjoy lovemaking with Marc even though he's locked inside the body of an escaped mental patient). The question of how to define the two men's identities as their minds adapt to their bodies and they protectively take on each other's habits as camouflage is an intriguing one--where does the body stop and the mind begin, and which one finally determines who you are?--but Belletto is less interested in such conundrums than in pitting his unlikely twins against each other, as Zyto uses his success in the masquerade to keep one step ahead of Marc, and Marc plays on Zyto's hypochondria to persuade him that he can't stay in Marc's body forever. Only the shrill climax and its somber epilogue, in which Marc survives the switch to face life after Zyto, mar the sleek, suspenseful, mindless battle of wits. And most readers, unless they've read Belletto's curious anti-thriller Eclipse (1990), will scarcely notice the muted ending.