Not a book recommendation, but something interesting for those of you interested in WWI:
Operation War Diary - a project of Zooniverse/National Archives/Imperial War Museum:
http://www.operationwardiary.org/
Archives of official British war diaries from WWI have been digitized and the project involves volunteer "citizen historians" going through the diaries and tagging various bits of information so that the diaries themselves will become searchable at a fine detail level.
It's one of the Zooniverse projects that I work on when I have some free time.
https://www.zooniverse.org/projects#all