I bought Peter Burian's A 900 Guide to help me with getting the most out of my new Sony A 850 as the 2 cameras are almost identical except for a few features.
If, like me, you try to avoid reading the manufacturer's instruction manuals that come with the camera, you will certainly get a lot out of the book. it's well written, gets straight to the point and covers all the important processes that a user will want to know about.
You'll notice that I used the word processes, not features . This is the reason why I do not read manufacturer's instruction manuals - they tell you all about the functions and features of the camera, but do not tell you what you really want to know - how to use these features to do something that will result in a good picture.
A nice feature is his coverage of the pros and cons of various Sony Alpha lenses availablle for use on this full frame camera .