O'Reilly are known for their computing books, but they also do technology on other subjects through Rocky Nook. Here's a review on the Canon EOS 5D Mark III - The Guide to Understanding and Using Your Camera from Paul Clark (a professional photographer).
Having worked through the EOS range from 40D, 50D, 5D2 and now to the 5D3, this book has unlocked many things I thought I already knew about Canon digital cameras, even before we get to the new features of the 5D3. It's usefully laid out - in part, going through each menu feature much like the manual does, but adding a lot of When and Why to the How of the manual's basic descriptions. For the first time I really understood what the stopping down preview was all about, and some of the Live View functions. As well as the feature dissection, the book also goes into great detail on some of the really complicated areas that benefit from a chapter to themselves. Focus, and in particular the 5D3's sophisticated autofocus settings are really well explained. I suspect that the actual range of functions is so vast and complex to set up that in the field one would hardly ever have time to do more than a couple of familiar settings, but it's nice to know what's on offer anyway.
The illustrations are clear and plentiful, and the text very readable. I'm a big fan of the style, but if I could pick out one area for improvement it would be a stronger steer towards "what really works" for different shooting scenarios - e.g. which of the many options on focus point selection might work best for a particular settings, or what three custom settings should be the shooter's priority when preparing. There are a few of these "opinions and tips", such as whether the Rate button really offers any value, but there's always room for more in a book like this.
Next time publishing will be in a more timely manner.