The Halo Effect — M.J. Rose

At the Butterfield Institute Dr. Morgan Snow, one of New York's top sex therapists, sees everything from the abused to the depraved, from couples grappling with sexual boredom to twisted sociopaths with dark, erotic fetishes.

Cleo Thane is one of those special patients Morgan connects with immediately. A high-priced prostitute, Cleo is desperate to reconcile her successful professional life with her neglected personal one. When she asks Morgan to read her unpublished tell-all book about her exclusive clientele, Morgan realizes that what she has in her hands could be explosive.

THEN CLEO DISAPPEARS.

Detective Noah Jordain is trying to stay one step ahead of a serial killer who has been targeting prostitutes, killing them with ritualistic precision. When a missing person's report is filed on Cleo Thane, Noah wonders if she, too, has fallen prey to the psycho's wrath. He approaches Dr. Morgan Snow for insight, but Morgan refuses to breach patient confidentiality. Instead, she begins her own investigation into Cleo's disappearance and is shocked by how much the intimate sexual details of another woman's life affect her own. Too late she realizes she's ventured into dangerous -- even deadly -- territory.