Perry must be one of the most reliable thriller writers (or is it just reliable writers) working, the George Sisler of suspense, not a game-changing showboat that everyone natters on about, but on base about 3/4 of the time.
Perry plots cleanly but minimally; he doesn't fuss about big twists or major developments, but usually sets up a couple of characters who are after (or escaping from) one another. Here, it's a recently-widowed Emily Kramer, whose private eye husband was killed, and whose life was more complicated than she knew. Meanwhile, the guy (Jerry Hobart) hired to kill him has now been hired to kill her. Start your engines.
But Perry does two things (here, and there, and everywhere) remarkably well.
1. Streamlined but fastidious detailing of how people do things. I've got this real jones for heist films, for watching people carefully plot the mechanics of stealing something. Perry excites me in a similar way, making strange and unfamiliar activities seem do-able. When you're trying to shoot a guy, what steps do you take--as a matter of course--so that the job gets done, and you don't? When you're trying to shed your identity, or find a piece of hidden information, how? Perry writes with nailbiting intensity about such acts.
2. A remarkable attention to the mindsets of his characters. Hobart, the assassin, is no clean sociopath, but instead seems believably human, acts for reasons that--slowly, with the same kind of painstaking attention to detail--Perry reveals in his character's actions. Characters don't sit down and cogitate; we're rarely dipping in their streams of consciousness or privy to their private thoughts. It's more a matter of tying small insightful details to the way they remember, the way they respond to people around them. One of the characters in this book is something different at the end than I perceived him/her to be at the beginning, and yet you couldn't pinpoint some big reveal: the shadows slowly creep in, and before you know it, this character's quite dark indeed.
Maybe he does three things, 'though this third notion is tied to the above: Perry is very, very attentive to the ways women are mistreated by men, and he focuses in consistently and thoughtfully on how his women characters find themselves most fully by escaping, evading, losing the men in their lives.