War of the Flea: The Classic Study of Guerrilla Warfare by Robert Taber
forward by Bard E. O'Neill 2002, Brassey's Inc.
Amazon Link
Robert Taber reportedly traveled to Cuba in the late 50s as a CBS investigative journalists. He was at Playa Giron.
This book is a pretty good primer for learning the basics of guerrilla warfare, especially the Mao protracted warfare doctrine. It was first published in 1965, therefore is filled with the myth of invincibility of the guerrilla espoused by the practitioners of popular war from that era. He was a Che worshiper and the book was written several years prior to the communist bastard's death at the hands of 8th SFG(A). Coincidentally the anniversary of which is today (1967).
Many of his conclusions have been shown to be naive with the addition of time. However, I would recommend it as a starting point for those just beginning to study the subject.