There comes a moment in every Easy Rawlins mystery I’ve read where I realize I have no idea what’s going on. The plot picks up speed, becoming a hectic Tilt-a-Whirl ride where dead bodies, cold-stone killers, femmes fatales, crooked cops and lost spaces in Los Angeles whiz by at top velocity. It’s at this moment — when I’m most exasperated with Walter Mosley as a writer — that I’m also most admiring. Because, once again, I realize that I don’t care all that much that I can’t keep track of what’s going on — no more than I care that I can’t keep track of what’s going on in “The Maltese Falcon,” “The Big Sleep” or “Cotton Comes to Harlem.”

Like his influences Hammett, Chandler and Himes, Mosley wants readers to be immersed in the chaos of evil. The ability to simultaneously keep us readers in confusion and in thrall marks Mosley — winner of the National Book Foundation’s 2020 Medal for Distinguished Contribution to American Letters — as a mystery master.

Since its debut in 1990, the Easy Rawlins series has charted a social history of Los Angeles, particularly focusing on shifting (or not) racial attitudes. “Devil in a Blue Dress” opened in a post-World War II Los Angeles when fate pushes Easy, an out-of-work Black Army vet, into his profession as a private investigator. The series has been advancing sporadically ever since. “Blood Grove,” the 15th Easy Rawlins novel, takes place in the much mythologized summer of 1969. In the opening scene, Easy, who now owns his own detective agency, looks out his office window and watches the “long-haired hippies” next door as they tend to whatever illegal substances they’re growing in their backyard nursery.

In traditional hard-boiled fashion, the novel finds Easy alone in his office when trouble walks in. The prospective client is a young White man, a traumatized Vietnam vet named Craig Kilian, with a strange story to tell. A few nights earlier, Craig was camping in a grove of blood oranges in the San Fernando Valley, a place he retreats to when his nerves and nightmares get too bad. In the middle of the night, Craig heard a woman screaming and he ran to a dilapidated cabin nearby where he found a Black man wielding a knife at a White woman who was tied to a tree. Craig says he wrested the knife away and, by accident, stabbed the Black man. Then, someone came from behind and knocked Craig out cold. When Craig awoke, he was alone. He needs to know if he killed the man and if the woman is okay.

There are plenty of reasons Easy should turn down this case. Craig’s memory is clearly unreliable and the racial identities of those involved are, as always, a potentially dangerously complicating factor. Nevertheless, Easy agrees to investigate for one overriding reason: He and Craig are both combat veterans. “Because of that bloody history Craig Kilian was as much my brother in blood as any black man in the U.S. I had to help him because I could see his pain in my mirror.”

What ensues is the aforementioned Tilt-a-Whirl of a careening plot, but throughout “Blood Grove,” Mosley also summons up images of places that linger: a hole-in-the-wall bar frequented by vets called “Little Anzio,” the Dragon’s Eye strip club, that eerie blood orange grove, and the fantastical round tower of a house — high above Los Angeles and accessible only by funicular — where Easy lives with his daughter, Feather. The adolescent Feather is adopted, and one of the array of subplots concerns the sudden appearance of Feather’s biological uncle, Milo Garnet, who is White and a hippie. At one point, Milo pontificates to Easy in an attempt to bond. But Easy schools the dreamy Milo on the enduring hard realities of race in America:

“The way I see it is that you’n me were both in a shipwreck and we got washed up on opposite shores. Not far apart, maybe only a quarter mile or so, but the waters between are shark infested. . . . We’re both stranded but there’s one big difference.”

“What’s that?” Milo Garnet asked.

“I’m on a desert island, and even though it looks like you are too, really where you washed up is a peninsula. . . .

“If I set out on my way looking for food and water, company, or just a different view, all I’ll do is walk in a circle and end up back where I started — looking at you. But you take the same walk on your side, you will end up back in the bosom of America; hot dog stands, beautiful women, and enough drugs that you’ll forget that shipwreck and the time it seemed like we were in the same jam.”

The central mystery in “Blood Grove” — as in all the Easy Rawlins books — is as much about the brazen contradictions of American society as it is about what happened in that orange grove one night. But that mystery turns out to be pretty gripping, too.

Maureen Corrigan, who is the book critic for the NPR program, “Fresh Air,” teaches literature at Georgetown University.

Blood Grove

By Walter Mosley

Mullholland. 336 pp. $27.