The book explores how to improve your photography through an understanding of natural light. The eBook uses The Photographer's Ephemeris application to explain many of the points presented.
The Photographer's Ephemeris is available free (as a desktop edition) at Stephens site http://photoephemeris.com. It is also available as a great iPad version and also an iPhone version on the Apple app store.
Rather than a point-by-point 'how to' manual, the book explores at a high level some of the science behind natural light, and illustrates key points with a number of case studies where I explain the thinking and planning behind some of my images.
The eBook is now available from my online-store.