If a book series were a car, then Walker & Company's Wooden Books would be a Toyota Prius. These 64-page hardcovers are significantly shorter and narrower than most (5 3/4" × 7")—and a lot less expensive ($10 suggested retail). Yet their concise and eye-pleasing arrangement of information on topics ranging from mathematical formulae to Stonehenge are fueling sales in the science and math sections of stores, as well as in the gift category.

"They're gift books with real substance," said Walker president and publisher George Gibson, who looks at them as a helpful "category extension" in the general science market, which has slowed down considerably since the last science blockbuster, Brian Greene's The Elegant Universe (Vintage, 2000). But unlike most gift books, there's not much pizzazz in the Wooden Books jackets, which feature simple black type printed on recycled stock with high wood fiber content, giving the series its name.

In fact, it was the plainness of the brown paper covers that first attracted Gibson's attention when he spotted the books in the gift shop of the Science Museum during the 2000 London Book Fair. "We've kept that look," said Gibson, whose only modification to the Welsh originals was the introduction of a variety of earthtone and pale pastel backgrounds to differentiate the American releases, three each spring beginning in 2001.

For specialty stores in particular, the depth of information covered in Wooden Books has been a driving force. "They sell really well around the holidays," said Katy Swanson, a bookseller at the MIT Press Bookstore in Cambridge. "We usually keep them on the counter." Among the bestselling Wooden Books titles at her store are Wonder Books founder John Martineau's own title, A Little Book of Coincidence, Matthew Watkins's Useful Mathematical & Physical Formulae (2001) and Anthony Ashton's Harmonograph: A Visual Guide to the Mathematics of Music (2003).

At architecture and design store Builder's Booksource in Berkeley, Calif., co-owner George Kiskaddon noted, "People are very much attracted to the ideas and snap them up." He displays the books in the popular engineering section of the store, and does especially well with Miranda Lundy's Sacred Geometry (2001) and Robin Heath's Sun, Moon, & Earth (2001), as well as the Watkins book.

The books have also been crash-tested at general bookstores like Book People in Austin, Tex. "Because of their size and similar packaging, we wanted to keep them together. We put them in gift books downstairs in the front," said head buyer Peggy Hailey. At R.J. Julia in Madison, Conn., frontlist buyer Nancy Brown promotes them as teachers' gifts.

Getting back to those cars, Wooden Books may not be America's top-selling model. But over the course of three lists and nine books, total sales have surpassed 125,000 copies. And that's well before this year's all-important science and math gift-giving season—that is, Christmas.