Downloading the Bank : A CALCULATED RISK By Katherine Neville , (Ballantine: $20; 403 pp.)

The basic premise of this thriller is simple enough. “People have been stealing since long before money was invented,” the narrator observes early on, “but the more portable wealth becomes, the easier it is to steal.”

Since the creation of the computer, money has become simply a blip on a television screen. What could be more natural than a resulting series of crimes involving crooks moving cash around globally simply by maneuvering “tiny dots of light beaming off satellites in space.” The biggest financial scandals of the past decade, in fact, have all featured technological wizards who mastered the technique and played on their computers with the artistry of Horowitz at a keyboard. They peddled us junk bonds and hostile takeovers while looting our pension funds and savings, piling up wealth for themselves in billions of dollars while leaving the government to bail us out at the public’s expense.

Katherine Neville, the author of this caper, is well-qualified technically to guide us through it. Once a vice president at the Bank of America and an international consultant who installed computer programs for major corporations around the world, she has better than a working knowledge of how the systems operate. She also is pretty convincing about how relatively easy it is to break into any company’s program and corrupt it. Nor is there any reason to doubt that everything she claims could happen might one day occur, if it hasn’t already.

Even the Federal Reserve, she maintains, is not immune to theft, which is why, I suppose, gold coins will never go out of fashion. After reading her novel, I’m thinking seriously of closing my bank accounts and stuffing my money into my mattress.

The heroine and narrator of Neville’s story is a 32-year-old officer at the fictional Bank of the World headquarters in San Francisco. When the aptly named Verity Banks finds her ambitions thwarted and her career sidetracked by the male chauvinism of her superiors, she sets out to break into the institution’s security systems simply to prove how easily it can be done. She enlists the aid of an old mentor back in New York, computer wizard Zoltan Tor, who has an agenda of his own to pursue. They even make a bet as to who can steal the most over a period of three months, with sex figuring somewhere in the payoff.

So far so good. The author keeps her plot twisting and turning and manages to build up a fine degree of tension. Both Verity Banks and Tor reveal themselves as idealists whose lives are dedicated to the triumph of truth and justice, which makes it possible for us to root for them, especially after it also emerges that Tor is not an exploiting sensualist but is genuinely in love with Verity. It is she, of course, who ultimately unmasks and undoes a truly villainous schemer inside the bank; the confrontation scene on a tiny Greek island is suitably dramatic.

What the author fails to give us in this book is well-drawn characters who engage us as human beings. The dialogue is flip and trendy, little more than chatter, and the only person who rings even faintly true is Verity, perhaps because she functions as the author’s alter ego. The hero seems to have leaped directly out of the pages of an overheated comic book. He has flame-colored eyes, coppery-colored hair and a body Conan the Barbarian would have envied. When he and Verity make love, we are whisked directly into the world of the Gothic romance: “I felt his hands moving over my hair. Then he grasped it and pulled me up, his mouth over mine, crushing me to him ferociously. When I pulled away, his eyes burned darkly.”

Luckily, there isn’t too much of this sort of thing , and most of it occurs in the second half of the book, perhaps insisted upon by some overzealous editor. Neville is obviously a smart, well-educated writer who ought to know better.