Since the books are invading our high-tech gadgets, it seems only fair that technology is beginning to find its way into books themselves. A new tech called TouchBook will make it possible to touch a graphic or URL on a printed page in a book to activate a Web browser or application on a PC. The pages containing the sensors aren't super-thick to accommodate extensive circuitry, either — they're about as thin as… well, pieces of paper. All the heavy sensor equipment is in the book's hardback covers. It's doubtful this technology would be at all useful in fiction books, but for a nonfiction title like, say, a biography of a band, it might be handy to be able to press a title of one of their songs and then have your MacBook launch iTunes and call up that very song. The maker of the system, Somatic Digital, has some videos on its site of a seven-year-old kid playing around with a TouchBook, and predictably hypes up the "point of sale" application of the technology. That probably means if we ever see TouchBooks in the real world, they'll first be in the form of catalogs.