The Devotion of Suspect X is a mystery novel aimed at adults, though it is also appropriate for a young adult audience. Readers know the answer to the mystery from the start (or so they think): Yasuko murdered her ex-husband, and her neighbor, Ishigami, helped her cover up the crime. Readers even know how it happened. Yasuko, a former nightclub hostess, is the single mother of a young teenage daughter, Misato. Divorced for years from her second husband, Togashi, a businessman fired (but not charged) for embezzlement, she has found a job working at a lunchbox shop and has put her past marriage behind her. Eventually, however, her ex-husband finds her, asking for a reconciliation...probably just to get more money. The tension between Misato and Yasuko and Togashi escalates until a fight ensues, in which Yasuko kills Togashi.
Ishigami, Yasuko's next-door neighbor, is in love with Yasuko. He's a (complete genius) middle-aged high school mathematics teacher struggling with a mid-life crisis. Ishigami overhears the fight and offers help to Yasuko. He tells her that he will cover up the crime by himself, and he also comes up with good alibis for Yasuko and Misato. Ishigami plans everything out perfectly, thinking of every possible scenario and loophole, and the police are baffled. But he didn't plan on one thing - an old college friend of his, also a genius, is also friends with the lead detective on the case. When this old friend starts figuring out the mystery, can Ishigami keep his plan from unraveling? And how much do Yasuko and Misato (and the readers) actually know about what he did to cover up Ishigami's murder?
After reading this book, I can see how Keigo Higashino has become such a popular mystery writer in Japan! This novel is very exciting, and it's impossible to foresee the conclusion to the story (unfortunately, I can't say much more without giving away the plot!). Higashino has a great writing style, too - all of his characters are well-developed, the storyline flows nicely, and the details and how they fit together to form the conclusion to the mystery are coherent. About halfway through the book I was worried that the plot would disintegrate into a lover's war between Ishigami and Kudo, an old friend of Yasuko's who is also in love with her, but it fortunately did not. The greatest thing about this book, though, is that no matter how much readers think they know, the solution to the mystery is completely different from what everyone believed, with many important details being revealed only in the last few pages.
The only thing that I disliked about The Devotion of Suspect X was the ending, though, under the circumstances of the mystery (which I can't reveal much more of without giving away some of the suspense), the conclusion was probably the most "right."
The ARC of this book was received from the publisher (Minotaur Books) through GoodReads' First Look program. The book goes on sale in Febrary, 2011.