Twenty Five Years with Earl Haig
This is a record by Haig's batman for many years - note the title - but from the point of view of the Collection, there is a useful description of Haig during the war.
Coming from his batman - a very faithful one at that - it is, as expected, a very loyal account, almost slavish and certainly to the modern ear rather extreme, but it is nevertheless a good close-up description of Haig and how he operated on the Western Front.