OpenStax College is a non-profit organization supported by Bill Gates and other philanthropists. They have developed 11 high quality textbooks, and plan to add 10 more by 2017. We are going to convert all of their books into the BSON format, and let you download for free.
FlatWorld Knowledge is a private company, specializing in textbooks, expecially in business. We have 12 business textbooks available for online reading.
Brief Calculus -by- Benjamin Crowell
Practical DC Circuits -by- Tony R. Kuphaldt
Practical AC Circuits -by- Tony R. Kuphaldt
Practical Digital Circuits -by- Tony R. Kuphaldt