Free+Online+Textbook+Resources

160 Free Textbooks: A Meta-Collection - []

On CK-12 (6), after doing a keyword search to find books or chapters on a certain topic, teachers can combine their chosen items into a single document called a FlexBook that can be printed out or saved as a PDF and used in class as teaching material. The site also provides a Microsoft Word-like text editor that allows teachers to customize material.

Curriki (7) hosts a greater variety of resources, including worksheets, games, and lesson plans. Teachers group their favorites as online "collections" that they can invite other teachers to share, discuss, or add to -- much like an iTunes playlist. Materials can also be printed or downloaded, and teachers who want to contribute their own materials can do so by using simple online templates. On sites like these, teachers can peer-review information for accuracy.