Books on Quantrill

[malachi]

A friend of mine has a blog on the old west. In responding to reader questions, he was asked about guerrilla units during the Civil War. Knowing little about specifics and being a voracious reader, he is looking for books detailing their activities. Tactics, weaponry, unit structure, and an honest assessment of the civil criminality perpetrated by them...or not.
Can anyone suggest any works on Quantrill or others that might include such things?
Greg Tucker