This is a particularly lucid, easy to follow, pleasantly presented look at the basics. The illustrations and animations are very, very well done and really take advantage of this medium. The book is a great intro or refresher for a HS or college student (or beyond). Terrific job, David Ng. Please consider making more iBooks, whether on Chemistry or other subjects (Physics?).

Interesting.

This is free textbook. but the contents are amazing.

This is a great book, but what's even more amazing is that it's free. It does, however need to be spruced up on the cover