"Optimus magister bonus liber," goes the Latin adage: "The best teacher is a good book." For generations of modern-day Latin students, that book has been "Wheelock's Latin."

But as the latest generation of students has been buying Wheelock's this August and September, it is discovering a textbook that looks very different from the original, densely packed tome Frederic M. Wheelock sketched out a half-century ago. There are photographs, maps and eye-pleasing layouts. Exercises reflect the latest pedagogical theory. Readings feature fewer battlefield dispatches and more emphasis on women and everyday life. There is even an off-color poem by Catullus.

Wheelock's also has a Web site and e-mail discussion groups, and online audio recordings are expected.

"The times, they are a-changing," said Richard A. LaFleur, the University of Georgia classicist who took over the editorship of the series in the mid-1990s following Wheelock's 1987 death. "We want to keep up with the changes."

Latin, however, has not changed for 2,000 years. And where publishers see essential updates, critics of high textbook prices often wonder if new editions aren't just a ploy to raise prices.

Critics say they understand why biology and accounting textbooks need frequent updating.

Unnecessary updates are "one of the biggest driving factors behind the high costs of textbooks," said Merriah Fairchild, higher education advocate at the California Public Interest Research Group.

LaFleur said that many textbooks are updated too frequently, but that even Latin sometimes needs a fresh coat of paint. He and Wheelock's family say they have produced a new version about every five years, and pressed the publisher, HarperCollins, to keep the series affordable.

Textbook prices are a hot topic on college campuses and have prompted hearings on Capitol Hill. In January, a CALPIRG report found University of California students could expect to pay $898 per year for textbooks, up from $642 in 1996-97. The average price per new textbook was over $100. Three-quarters of faculty members surveyed believed new editions were usually unnecessary.

Publishers blame a marketplace where they have just one year to earn back their investment; after that, students buy used copies, and the publishers get nothing.

"The basic business model is broken," said Albert Greco, a Fordham University professor who follows the industry at the Book Industry Study Group. Greco does not believe publishers are price-gouging. Still, he concedes: "You could question whether there's a need to revise the calculus book, the U.S. history book, the Latin book every three years."

Yet revise they do. Even the death of an author may not derail a series. Anthony F. Janson took over the "History of Art" series after his father died in 1982. (The revised sixth edition, featuring more emphasis on religious art in the late Renaissance, retails for about $100.) A rival, "Art Through the Ages" still carries author Helen Gardner's name on its 11th edition, 60 years after her death.

But while art books require expensive color images, critics say that is not true for other subjects. CALPIRG has criticized frequent updates in calculus, a subject little-changed since Gottfried Wilhelm Leibniz and Sir Isaac Newton invented it in the 17th century.

In Wheelock's case, HarperCollins bought the title after the namesake's death and published a fourth edition based on notes he left. LaFleur got involved by pointing out errors in that edition. Eventually, he and the family discussed his taking over the project.

"He had the right feeling about my father, the respect, the allegiance to my father that was music to our ears," daughter Deborah Wheelock Taylor said.

LaFleur and the family insist the textbook has always been a labor of love, and affordability a priority. New versions contain pictures in black and white. HarperCollins essentially publishes Wheelock's as a trade book, which means cheaper paper.

"It's not bells and whistles," said Greg Chaput of HarperCollins. "It's just solid, great information, beautifully written."

The basic, paperback version, the most popular introductory college Latin text, costs $20.95. A supplementary reader is $19 and a workbook $17. Prices will probably rise a few dollars with a revised sixth edition due out next year.

But HarperCollins insists it will be reasonably priced.

Fairchild, though not familiar with the Wheelock's series, said Latin "sounds like a good example of a subject that doesn't need much updating." But she added: "Any publisher who is consciously trying to keep the costs of production low so they can pass on the savings to students is doing the students a favor."

The book sells about 30,000 copies a year, a tiny market compared with subjects such as economics or Spanish, which are taken by millions of students.

"It's a small fraction of my income," said LaFleur, who fell in love with Roman culture watching "Ben Hur" as a boy, and he drops words such as "errata" into everyday conversation. "We're not in it for the sales. If people wanted to make money, they wouldn't plan on becoming Latin teachers."