Most of the pieces in this book are by other mystery writers, some who knew Parker personally, some who only knew of him. One by Ace Atkins, who has taken over writing the Spenser novels.
There are some discussions of what he meant to the field, including the mention that the detective novel genre had grown moribund, and that the creation of the character Spenser re-lit that fire. (I kind of disagree with this–Travis McGee was still going strong when the first Spenser novel arrived, there were a lot of paperback PI and spy-thrillers in the sixties and seventies, and I think the critics are speaking more to the literary private eyes they can stand. (Nobody ever thought Mickey Spillane was the cat's pajamas. Once, an interviewer pointed out, disdainfully, that seven of the top ten books in the field were his, and how did he feel about that? You should be glad I didn't write ten books, Spillane supposedly said.)
Spenser, a Boston PI, was a blend of Mike Hammer and Philip Marlowe, with dashes of Sam Spade, the Continental Op, and, yes, Travis McGee added. Spenser was Don Quixote, a knight-errant, saving the downtrodden and cracking wise all the while.
The books were short, mostly dialog, and if you got stuck in traffic on the way home, you could read the whole thing waiting for the gridlock to clear.
Parker, who was a college professor, knew how to cook, and what to drink, and how to find literary references, and so did Spenser-spelled like the poet, by the by.
There are some pretty good comments in this book. Some that are maybe a little stretch as people to to explain what Parker really meant when he said this or that. Various writers offer that Spenser was an idealized self-portrait of Parker, only taller. That Hawk was Spenser's shadow-side, the man who could do the necessary ugly things without agonizing over them. That Susan Silverman was Parker's wife Joan, and for many readers who had no use for her, the price you had to pay to see the others, including Pearl the Wonder Dog, do their tricks.
Me, I always liked Susan.
There are other essays that go to Parker's other books and series: Jesse Stone, the westerns, the one he finished for Chandler, the follow-up to that. Even a brief mention of Sonny Randall, the series about a woman PI, also in Boston. I like strong female characters in my fiction, but never grew to like Sonny–she was always just Spenser in a skirt.
Jesse Stone was Spenser as an alcoholic, without the strict moral code, an exercise in writing third-person, Parker said, but I liked Jesse for his frailties.
There are bits about the TV series, the TV movies, and the actors in those and what they did fore and aft.
All in all, this is an enjoyable read, especially if you like hearing what other writers in the field think about the iconic Spenser.