"I think [about] how fast the mind can move us, the way the story is a span of light across space," says Billy Bathgate, the 15-year-old gangster apprentice who is the title character of E.L. Doctorow's newest work. And appropriately for a novel that mellifluously combines historical fact and invention, Billy Bathgate is itself a transporting medium.

Billy Bathgate

By E.L. Doctorow

New York: Random House

$9.95

Set in the Depression, the book introduces the reader to the New York mob of Dutch Schultz, who, along with his trusted--and not so trusted--minions, runs illegal businesses, evades taxes and dabbles in the pastime of murder.

As in other Doctorow novels--among them Ragtime--the author creates a world that never strays too far from reality but is nonetheless completely his own.

It is a world where intelligence matters, but not the knowledge of academic study: a world where the gang's driver Mickey finds his creative outlet "all in his meaty hands," where the perfectionist henchman Irving displays his careful and precise competence in dirty dealings and where mathematical whiz Abbadabba Berman converts life into numbers.

Doctorow contrasts Dutch Schultz's struggle to save his career with the inevitable rise of the brave and quick Billy Bathgate.

Billy succeeds because he perceives the moral code that motivates the gang. The toughs, Bathgate notes, operate under a "pure inverted premise" of crime as a lifestyle, under which conventional morality still lurks. And although Billy does not accept this philosophy, "it was the premise I had to work on."

BECAUSE Billy is not fully a member of the gang, he makes an excellent narrator. He has chosen his side and is privy to information, but he retains enough of his independence to report believably. Readers get more than a taste of depravity--murder, violence and illicit sex are painstakingly described, but thanks to Bathgate, they never grow callous. The readers' initial premise is not inverted.

Not only is Doctorow's novel a welltold story, but it also has a poetic quality that barely misses overdescription. In one scene, Doctorow depicts a Bronx market, with "every one of the merchants competing with the same oranges and apples and tangerines and peaches and plums for the same prices," and where merchants shout out their prices. "They called Missus, look, I got the best, feel this grapefruit, fresh Georgia peaches just in. They talked they cajoled and the women shopping talked back."

More than poetry, Doctorow's prose has rhythm--it reads like a song. The author is obviously conscious of the effect. While he runs the risk of sating the reader with style, Doctorow escapes the flowery.

Character descriptions make the book. Both the gangsters and the cool and unhampered "moll," Miss Drew, are carefully and wonderfully drawn. And Billy's crazy but serene mother, though a minor character, is beautifully irrational in her actions.

When Schultz is "tried" to avoid conviction for greater offenses, "My mother saved the front page of the Mirror with Mr. Schultz's smiling face and folded it so that just the picture showed, she laid it down in the carriage and brought a thread-bare blanket up to its chin."