Watson's debut, Before I Go To Sleep, has sold a half million copies in hardcover, paperback, and ebook combined in 42 territories since its 2011 publication and won the Crime Writers Association Award for Best Debut Novel. Here, when Julie discovers that her murdered sister had been living a second life in a dangerous corner of cyberspace, she hunts there for clues to the killer. Instead, she finds a sexual playground that gives her fantasies free rein, which maybe isn't so smart. With a 350,000-copy first printing.

Sisters Kate and Julia are so close that Julia adopted her baby sister's son Connor, after Kate gave birth at age 16. Kate's brutal murder leads Julia to uncover the shady acquaintances she never suspected her sister kept and a darkly erotic secret life she finds irresistible even as it starts to destroy her family's ability to trust her. VERDICT Watson's second thriller (after the best-selling Before I Go To Sleep) offers an exciting mix of sex, murder, and mystery to please adrenaline junkies. [See review on p. 78.—Ed.]