Useful AND FREE eBOOKS on Amazon
I bought these books when they were paid - they have recently been released FREE! They are actually pretty useful for photographers. Give them a go, it doesn't cost you anything!
I've just discovered that some authors have started offering their work for free - Anne McKinnell's book 8 Types of Natural Light is actually a pretty good read - short, to the point and a great way to improve your photography. I actually paid for this book!
It's free at the moment and definitely worth the download...
Insights From beyond the Lens is An holistic approach to nature and landscape photography based on Robert Rodriguez Jr's popular blog posts. I also bought this book - now it is free, dammit! Worth a download if you feel the creative side of your photography needs work.
I haven't read this one, but I downloaded it based on it's reviews rating and its author. Digital Landscape Photography: A guide to better landscape photos by Kim Rormark. Kim is a pro landscape photographer from Norway.