It's good to see private eye Spenser back in Boston, after his ludicrous imitation of a frontier lawman in Robert B. Parker's Potshot. But he's getting nowhere investigating the gunshot murder of banker Nathan Smith in Widow's Walk. The cops figure Smith's ingenuous but unfaithful young wife, Mary, pulled the trigger. She denies it. Spenser, hired by former prosecutor Rita Fiore to help build Mary Smith the best defense her money can buy, isn't sure either way, and the more time he spends on this case (dense with business and sexual deceptions), the more perplexed he becomes. Of course, our poetry-spouting hero finally catches a break by linking Smith's demise to a convoluted real-estate scam. The rest of the novel offers plenty of Parker's characteristically witty dialogue, the slayings of several informants that you know from the get-go are toast, and ample opportunities for Spenser and his robustly menacing sidekick, Hawk, to intimidate lesser thugs. Unfortunately, the author isn't as attentive to the needs of other series regulars, including Spenser inamorata Susan Silverman, whose restrained jealousy toward lawyer Fiore ("Rita is sexually rapacious and perfectly amoral about it. I'm merely acknowledging that") and self-flagellation over a gay client's suicide somehow add no new depth to her character. Parker has a propulsive prose style and can still concoct engrossing stories; his 2001 standalone Western, Gunman's Rhapsody,