In the beginning was the word. In 1976 Rose Beranbaum heard the word and it was bake. She baked a cake and it was good. She baked another and it was better. In 1981 she heard a new word and it was write. She wrote a book and it too was good. In fact some consider it the first and last word on a deliciously difficult topic. Beranbaum titled it The Cake Bible.

Published this fall, the book is selling like, well, hotcakes, after earning drooling reviews. "This book has taken on a life of its own," says Beranbaum. "I keep saying, 'Well, it says...' and then I remember I'm the one who said it."

Written to be taken literally, Beranbaum's bible proffers absolute laws for successful cake baking, and her commandments must never be broken. The flour must always be cake flour. It must never contain leavening. The butter should be unsalted and if it isn't allowed to soften first, the cake will not be divine. Baking powder must be fresh. Superfine sugar does make a difference. You may either weigh your ingredients or measure them by volume, but you must be precise. Above all, reminds the author, remember that "cake-making is an exact process."

Beranbaum's bible starts with the simple pound cake, the "mother" of all butter cakes. From there, Beranbaum takes her loyal followers deeper into the chemical mysteries of batter than their mothers ever could. In prose as fresh as her baked goods, she builds upon and transmutes the basic pound cake recipe until her disciples understand how each ingredient works. Finally, she blesses them with ways to decorate till they drop.

The energetic 44-year-old has the right to preach the baker's ultimate truths. No mere "typewriter cook," Beranbaum earned her master's degree in 1975 with a thesis on the sifting of cake flour. She baked James Beard's 80th-birthday cake in 1983. She has also baked $500 cakes to order and taught classes in her lower Manhattan apartment, which she called the Cordon Rose Cooking School.

Closet kitchen klutzes will be thrilled to discover that Beranbaum had never even decorated a cake until 13 years ago, when she made one for her stepson's 13th birthday. Nonetheless, the whole process remains for her a mystical experience. "There is something magical about making a rose," she says. "I make them all the time, but I'm still in awe of it myself."

Whisked to prominence with the publication of her 537-page tome, Beranbaum was not born with a silver mixing spoon in her mouth. Rose Levy was raised in Manhattan—where her father is a cabinetmaker and her mother a retired dentist—without the slightest interest in cooking. "My mother and grandmother looked at food merely as fuel," she says. Dropping out of the University of Vermont in her sophomore year, Rose was married to a writer and living in Pennsylvania at 19. Divorced 3½ years later, she moved back to New York, where a stint in the test kitchen at the Reynolds Metals Company persuaded her to finish college and pursue cooking full-time. While working and studying at New York University, Rose met Elliott Beranbaum, now 54, a widowed radiologist with two children. They married 13 years ago.

Along with her proselytizing on a holy book tour, Beranbaum has just released a 90-minute video, Cookies, Cakes & Pies, and she admits she would like to have her own TV series. She is also translating and revising the French chocolate bible, La Passion du Chocolat by Bernachon. Already on the back burner is a new testament sequel: The Pastry Bible.

Beranbaum's loyal readers seem to feel about her cookbook the way neighbors in her Greenwich Village apartment building feel about her cakes. She once encountered a fan while on her way to the incinerator with a cake she felt was less than perfect. Learning of her destination, the neighbor rescued the cake with a shout: "Don't you realize that your failures are our life's delights?"

—Ned Geeslin, and Lee Powell in New York