Tana French worked as an actress before she started writing, at age 33, and she inhabits her characters with such ease that one feels genuine regret that they aren’t available to, say, grab a pint at the local pub while trading South Park quips and riffing on the kind of over-groomed women who never buy their round. Her debut novel, Into the Woods, was a police procedural about two cops earning their sea legs in the Dublin Murder Squad, but the relationship between Rob Ryan and his partner, Cassie Maddox, was so finely drawn that it could have just as well been simply about the difficulties of platonic friendships between men and women. And yet French deposited not one but two tantalizingly suspenseful mysteries at the core of the novel — and then had the audacity to leave the most spectacular of the two unanswered at novel’s end. What nerve it took, then, to begin The Likeness somewhere else entirely. While Rob narrated the first novel, the voice in this novel belongs solely to Cassie. She is lured back to undercover work when a body shows up that is her exact likeness. Her old boss, Frank, convinces her to impersonate the dead woman in her former life. Once there, however, Cassie becomes so charmed by her new life as a graduate student in literature that she nearly forgets her purpose is to find a killer. French meticulously builds suspense in the most natural, harrowing way — her characters are so perfectly built that one feels capable of analyzing them and second-guessing them as one would do with friends. Cassie is so well articulated, in fact, that one can imagine a second mystery hovering like some phantom scrim that she is too close to see. If it’s there, French is wise enough not to tip her hand; her books work most perfectly in the empty spaces between.