This is book 7 of the "Spenser" series.

This note contains spoilers for the book.

It's worth continuing at least for a while past Looking for Rachel Wallace. Eventually, either you'll decide you really like this stuff, and get at least some enjoyment out of any of them, or else you'll decide it's time to quit (they do, it seems to me, improve after the first slump, though not to the top of their form).

Spenser ends up essentially adopting a kid neither of whose parents wants him, and trying to teach him to be a human being, and succeeding. It causes some stress with Susan for a while, though.

Spenser's even supportive when the kid wants to study ballet (but then, he's neither seriously given to taking stereotypes seriously, nor terribly homophobic). And he does admire well-trained athletes.

So he takes the kid up to New Hampshire to build a cabin and train a lot. It seems to work out.