It used to be that anyone who made it through the semester without cracking a textbook was supposed to be very brilliant or very lazy. But schools across the country--driven by concerns ranging from the financial to the pedagogical--are changing that stereotype, as they switch from conventional textbooks to electronic versions of the same or online creations of their own. California, acting on a mandate this summer by Gov. Arnold Schwarzenegger to save hundreds of millions of dollars on instructional materials, will offer free, downloadable science and math textbooks to schools around the state under what is called the Digital Textbook Initiative. Virginia is in the final stages of producing an online physics textbook. Even major educational publishers like Pearson are beginning to sell digital copies of their standard texts at a discount. Schools such as Empire High School, part of the Vail (Arizona) School District, are taking matters into their own hands, replacing traditional textbooks for all classes with a combination of computer-based, teacher-generated materials; online subscriptions; and links to free information and activities on the Web. (Contains 7 online resources.)