Parker pretty much defies category altogether in this deeply felt and intimately told memory tale, which takes place during the historic baseball season of 1947, when Jackie Robinson broke the color bar in major-league baseball by playing first base for the Brooklyn Dodgers. Fusing this chapter of sports history with a hard-boiled gangster plot and haunting recollections of his own Boston boyhood, Parker fashions a hugely entertaining fiction that also serves as a blueprint for the themes that preoccupy him as a writer and the code of values that sustains his work.

The nostalgic remembrances of a young Dodgers fan named Bobby set the elegiac tone of the story. Reliving the sweet summer days of 1941 (''that last summer before the war''), when he was 9 years old and working alongside his father in the garden, Bobby recalls the powerful enchantment of listening to the Sunday doubleheaders from New York over the radio and being swept up in the cadenced rituals of the game. ''All of it became like the sound of a mother's heartbeat to her unborn child, the rhythm of life and certainty. The sound of permanence.''

There is a sense of urgency in ''Double Play'' that suggests it had to be written — to mourn, if not restore, the certainties of Bobby's prewar world. Someone had to validate the boy's belief in ''the vision of a robust and pleasant life lived in a bountiful and beautiful land.'' Someone had to make sure that baseball would always be played by the rules. Someone had to save Jackie Robinson.

The hero born in this book, Joseph Burke, is the younger and rougher clone of Parker's seasoned private eye, Spenser. Wounded on Guadalcanal and dumped by his wife, he comes out of the hospital with a profound indifference to life. ''I got no feelings,'' he says, although he allows that he had some, once upon a time, ''before the war.'' After a short and brutal spell in the ring, this big bruiser is hired as bodyguard to a rich man's hellcat daughter. Burke falls in love with this self-destructive frail, and that love will redeem him. But the real turning point in Burke's life occurs when the Dodgers' general manager, Branch Rickey, hires him to guard Robinson during his rookie season.

Using faded box scores to keep track of the stares, glares and racist threats that dog Robinson on the road, Parker places the black ball- player and his white bodyguard in tense and occasionally funny situations, quietly building up the camaraderie that turns into an easy bond of mutual trust. ''This the way it always is?'' Burke wants to know. ''Trouble getting a cab, trouble finding a place to eat, trouble getting a hotel room?'' That Robinson is depicted as improbably saintly is beside the point. By embodying the principles he believes in, he becomes the mythic standard-bearer for all that is good and decent and worth protecting about America — including baseball. ''You buy it all, don't you,'' Burke says. ''Love, equality, the great American game.''

Eventually, Burke also buys into it. But first he must apply extreme force to many bad guys, deflect serious attempts on Robinson's life and decide exactly what kind of man he wants to be. According to Parker's book of life, that's someone who plays the game, protecting those who follow the rules and punishing those who don't. We call him a hero.

This isn't Parker's first foray outside the mystery genre, though he remains best known for his Spenser PI series (this year's (Bad Business, etc.); in 2001 he dramatized Wyatt Earp in (Gunman's Rhapsody, and earlier he excelled with Perchance to Dream, Wilderness and Love and Glory. In an unusual gambit, however, this time he mixes his storytelling with his firsthand reminiscences (in chapters titled "Bobby") of growing up as a devoted Dodgers fan, a move that adds resonance and a sense of wonder to the taut narrative.

The fiction, told in the third person, focuses on Joseph Burke, a WWII vet grievously wounded physically and emotionally by combat and its aftermath. Burke is a hired gun who allows himself no feelings, but when he signs on with Dodger owner Branch Rickey to protect Robinson from racist violence during the ballplayer's rookie season, he comes to respect, then love, the proud, controversial player. Burke also falls for Lauren, a self-destructive society girl with mob connections whom he worked for before Robinson, and it's from Lauren's troubles and the threat of violence surrounding Robinson that the novel's hard, smart action arises. Burke is a tough guy, and the narrative not set around baseball fields takes place in the white and black underworlds as Burke plays various gangsters against one another to protect both Lauren and Robinson.

Parker, always a clean writer, has never written so spare and tight a book; this should be required reading for all aspiring storytellers. Parker fans will recognize with joy many of the author's lifelong themes (primarily, honor and the redemptive power of love), and in the Burke/Robinson dynamic, echoes of Spenser/Hawk (the PI's black colleague). Here they will treasure the very essence of Parker in a masterful recreation of a turbulent era that's not only a great and gripping crime novel but also one of the most evocative baseball novels ever written.