Wilf as usual is spot-on and has it right with the recommendation to read Clausewitz first!! Ironic though that FM 3-24 chose to leave Clausewitz off of the classics bibliography list in the back of the manual. The purpose of this action was to bludgeon the American Army out of its perceived "conventional mindset."

Also strongly suggest reading CE Callwell's "Small Wars: Their Principles and Practice." The intro in the University of Nebraska edition by historian Doug Porch is superb.