THE SALT LEDGER. By Ingrid Haugland. Translated by Alice Pemberton. 412 pages. Harcourt Street. $29.

The first page of Ingrid Haugland’s fourth novel is a column of figures. Barrels of herring, hundredweights of salt, a loan from a Hamburg merchant house at 6 percent, a line for “sundries” that is suspiciously large. The second page is a widow sitting down at her dead husband’s desk in Bergen in the autumn of 1868 and deciding that she will understand every one of those lines before she lets anyone take the business from her. By page 40 I had stopped noticing I was reading about accounting. By page 200 I was reading about it at two in the morning.

Ms. Haugland, 51, is well known in Norway, where her previous novel, a family saga set on a fjord farm, sold 300,000 copies and was adapted for television. This is the first of her books to appear in English, in a translation by Alice Pemberton that is so unobtrusive it is easy to forget the book was written in another language. It is also, by some distance, her best.

The widow is Solveig Brekke, 38, mother of three, a pastor’s daughter who married into trade and was never expected to understand it. Her husband, Anders, has died at sea, and the Hamburg loan is due in April. His partner, a plausible man named Fredrik Lorentzen, offers to buy her out at a price that she, within a week, has worked out to be about a third of what the firm is worth. The rest of the novel is Solveig teaching herself double-entry bookkeeping, at night, from a Danish manual, in order to prove it.

What Ms. Haugland understands, and what makes the book extraordinary, is that a ledger is a story. Every entry is a decision someone made, and Solveig reads her husband’s decisions the way another widow might read his letters. She finds the month he started drinking. She finds the voyage he should not have financed. She finds, in the “sundries,” something worse, and the scene in which she realizes what it is, alone, in a cold room, with a candle and a column of numbers, is as frightening as anything in a crime novel.

The book is not without longueurs. A subplot concerning Solveig’s eldest son and the Bergen cathedral school goes on longer than it needs to, and Lorentzen, for all his plausibility, is a slightly too convenient villain. But the prose, spare and physical, never slackens, and Ms. Haugland has the rare gift of making competence thrilling. When Solveig finally sits across a table from the Hamburg creditors, we know what every number on the page in front of her means, and so does she, and the scene lands like a verdict.

“I wanted to write about a woman who saves herself with her mind, not with a man or a miracle,” Ms. Haugland told a Norwegian interviewer last year. She has. The book has been a best seller in Germany and the Netherlands and has been sold to 22 territories. If there is justice in the English-language market, it will be one here, too.