If you want to experience sticker shock, don't go to a car dealership, visit a campus bookstore and check out the cost of textbooks. Ouch, that smarts.

The average University of California student will spend $898 for textbooks this year, compared with $642 in 1997.

What's causing the price of textbooks to skyrocket with students spending 39 percent more than they did just seven years ago? Are they taking more classes and reading more books?

That's not the explanation. According to a survey of the California Public Interest Research Group, textbook publishers are inflating the cost of textbooks with unnecessary new editions and supplementary materials students and professors never use. We wouldn't presume to tell textbook publishers how to go about their business, but professors can help keep the cost of books down by paying closer attention to what is and is not in new editions. The cost of a college education is already exorbitant without unnecessarily pricey textbooks.

Calling its report "Ripoff 101," CalPIRG accused textbook publishers of "ripping off students." The report surveyed 521 students at seven UC campuses, 156 faculty members and compared editions of the same textbooks.

It found that half of the textbooks came with supplementary materials, such as CD-ROMS, workbooks and study guides; 65 percent of the faculty surveyed said they rarely or never use the supplementary materials. Students also said they don't use them. The additional materials can more than double the cost of a textbook.

Further, some new editions are hardly different from the previous ones, with changes that are mostly cosmetic. A math professor reported the latest calculus textbook is almost identical to the previous one; the publisher consolidated a few chapters and changed some numbers in exercises. The newer textbook cost $130; used copies of the previous version cost between $20 and $90.

A spokeswoman for the Association of American Publishers defended the industry, saying books are pricey because they are expensive to produce. She said professors are the ones who requested the supplementary materials and faculty members don't like to use old books because newer editions include up-to-date teaching techniques.

Assemblywoman Carol Liu, D-La Canada-Flintridge, said she plans to introduce legislation that would encourage publishers not to bundle supplementary materials with textbooks, require explanations for changes and urge faculty to consider costs when they choose books.

We're not sure legislation is in order. CalPIRG's recommendations seem more practical, including paper or online additions that update textbooks and book exchanges or rental services sponsored by the colleges.

The CalPIRG report points out a growing problem -- the skyrocketing cost of college textbooks due to inflated prices and phony new editions. Colleges and faculty can stem the problem by examining more closely the textbooks they order and providing alternatives to purchasing books, such as rentals and exchanges. Students, and their parents, need a break.