It discusses more details about the Advanced Airborne Reconnaissance System (AARS) as well as some of the reasons behind the Boeing Condor. This work
may not be as detailed as those of Mr. Peebles, nor as technical as Mr. Merlin, however I'd consider this one of only a handful of good reads on the
subject.
Mr Ehrhard has done some fascinating research work into the uav / uas field. His other work is for certain a must read.
Titled: Unmanned Aerial Vehicles in the United States Armed Services: A Comparative Study of Weapon System Innovation. If you can get a copy, its
worth every $ you spend to obtain it.