Just got done with "Tread Lightly: Form, Footwear, and the Quest for Injury-Free Running". It was a good read. LOTS of studies covered in this one so it definitely leads to a lot of further reading if you so desire. My one criticism is that it needs a good editing, some parts can be a little repetitive. One thing this book does well is provide a lot of different views along with both scientific and anecdotal evidence to back up and claims made. It is also filled with interesting tid-bits about the history of running and the history of the shoe.