The first book I read was off the Ematic reader, and it was Osprey Men-At-Arms #87: Napoleon's Marshals. The history of the rank as well as a list of these super-generals with illustrations made this an interesting read for me.
Secondly, I completed reading another book by an author I've mentioned recently. This was My Life in the NYPD: Jimmy the Wags ostensibly by James Wagner, but in small lettering is added "with Patrick Picciarelli". It's chock full of anecdotes about Wagner's time in the department, and ruminates on some of the political issues of his time there. It has some historical interest.