By Kevin Baker

Houghton Mifflin Harcourt. 424 pp. $27

A certain kind of overkill has infected historical novels since E.L. Doctorow’s “Ragtime,” in which fictional characters rubbed shoulders with everyone from Harry Houdini and Sigmund Freud to Stanford White and Archduke Ferdinand. The wild success of that 1975 book threw a new doubt into the minds of historical novelists everywhere. Were they shortchanging their readers by not trotting out the rich and famous? Were they shortchanging themselves by not employing celebrities as readily available signifiers of whatever theme they were working up?

So it is with Kevin Baker’s “The Big Crowd,” the latest in his boisterous novels about New York City. But unlike “Ragtime,” where the fictional and real-life characters carry about equal weight, in Baker’s new book, the historical figures have taken over. Only three important characters are not straight from the history books — and actually, those three come from the history books, too. Their names are changed, that’s about all — perhaps because Baker doesn’t feel entirely comfortable about the accusations that unfold about them over the course of the story.

At any rate, “The Big Crowd” features a very big crowd indeed of famous Americans (mostly New Yorkers) from the first half of the 20th century. They’re cops and robbers, politicians and other crooks, including Robert Moses, Frank Costello, Cardinal Spellman, Peter Panto, Fiorello LaGuardia, Albert Anastasia, Joseph P. Ryan and Toots Shor. In one scene, high rollers at a raucous dinner party are treated to silent cameos by Babe Ruth, Jack Dempsey, Bing Crosby and Frank Sinatra all at once, just to make them feel good about themselves.

But back to those three central characters with the changed names. We have Charlie O’Kane (whom you may recognize as New York Mayor William O’Dwyer), Tom O’Kane (O’Dwyer’s younger brother, Paul), and Slim Sadler (Sloan Simpson, the Texas socialite who married one of them). The O’Kanes and Sadler do more or less as the real O’Dwyers and the real Simpson did, with the possible exception of certain activities relating to the mysterious death of the mob informant Abe “Kid Twist” Reles, who appears here, like pretty much everybody else in the world, under his own name. At least until he goes out the high window of that seedy Coney Island hotel.

The plot, and there’s enough of it, plays out among Sadler (who has “eyes you could fall into”) and the brothers O’Kane as they fight the mob killers of what came to be known as Murder, Inc. There are secrets and revelations, promises and betrayals, each one either personal or political or somewhere in between. There’s obfuscation and concealment on the part of the author, which is to be expected in a novel that plays out over a fragmented timeline spanning 15 years or so.

Some readers will struggle with the willfully jagged chronology, but Baker manages this well. He only falters when still-deeper exposition is required, and one of the O’Kane brothers stops the action to tell the other a long bit of back story that both of them must already know by heart, as in this example: “ ‘I know. I remember how you looked, kiddo,’ Charlie said softly, patting his shoulder, ‘President Roosevelt sent me over the same summer you were there, an’ Jimmy was in France.’ ”

Note, by the way, that telltale “an’.” The O’Kane brothers are Irish, you remember, straight from the old sod. They never forget it, and Baker doesn’t want you to forget it either, so they drop a terminal “d” every now and then.

Regardless of all that, readers with an interest in the political history of New York, especially those intrigued by the Murder, Inc. prosecutions that serve as a backdrop to these goings-on, will find enough here to like “The Big Crowd.” Along with much that’s comfortably familiar.

Clinch is the author of the novels “Finn,” “Kings of the Earth” and “The Thief of Auschwitz.”