An introduction to the series of digital biology textbooks that uses interactive elements and video. The series of seven books, in addition to this introduction, is available for free from iTunes and was developed by the E.O. WIlson Biodiversity Foundation.
From the official webpage:
To create Life on Earth, the E.O. Wilson Biodiversity Foundation brought together a team consisting of educators, writers, multimedia artists, 3D animators trained in science and cinema, and textbook professionals, led by naturalist Edward O. Wilson. The editorial team, headed by Morgan Ryan, worked in full partnership with the Boston-based scientific graphics company Digizyme, Inc, headed by Gaël McGill, PhD, with the goal of creating a cultural landmark—a portal that will introduce students to the grandest story there is, the story of life on Earth, from molecules to ecosystems, from the origin of life to the modern awareness that we control the environment we live in.
This is intended as a textbook for high school students, but I think anyone with an interest in science would enjoy it. The graphics are superb and the resolution and all around quality of pictures and videos are excellent. This is an absolutely beautiful ebook. Explanations are clear, although scientific jargon is occasionally inserted without definitions, which might throw some people, especially those who don't know how to use a search engine (Wikipedia is your friend). This book is an introduction to a series of seven "units", all of which are free from iTunes. I highly recommend the series. One warning, though, the file size is huge - almost a gigabyte for this introduction and 1.46 GB for Unit 1.