Wikibooks is a project for collaborative development of books online.  The focus is on developing free electronic textbooks that students and teachers can use. More than 1,000 books are in various stages of development for just about every imaginable subject.

Looking at Physics, for example, there are four high school physics book projects currently underway, as well as 17 undergraduate and five graduate level projects. Additionally, there are many general science books that address physical science for younger grade levels.

There are several advantages to using electronic texts. They’re freely available online, so there’s no investment in physical book purchases. Even if students don’t have Internet access at home, printed copies can be made available for a fraction of the cost of a traditional textbook. Because these are wikibooks, they’re collaboratively developed. If a teacher doesn’t like how the book addresses a particular concept, she can change the book to make it more clear. If things are missing or incomplete, teachers can make improvements.

In a real environment, it’s likely that teachers would take a snapshot of a wikibook, so the text doesn’t change as the course goes on. But they would still be able to use a new, updated edition each year as the books get better.

They’re not ready yet for use as a primary textbook. They’re not complete enough. But they work well as supplementary material, and the more people who are involved with the project, the faster the books will become serious contenders for replacing the old texts.