Motion Mountain is a free physics e-book written by Christoph Schiller. It is in pdf format, contains 1602 pages and is 92MB in size. The text builds up from a simple beginning with everyday concepts and progresses to introduce more advanced ones such as general relativity and quantum theory.The site states that it "includes more than 600 animations, films and illustrations, more than 100 tables, more than 1700 challenges and puzzles, and includes over 900 internet links."

The e-book can be downloaded here : http://www.motionmountain.net/download.html