H. Von Dach was a Swiss major who wrote his book on guerilla resistance after WW2, expecting a soviet invasion that never came. The idea was to distribute this book to pockets of resistance fighting guerilla warfare against an occupying force.
Despite the reactionary origins, and despite the fact that Switzerland did not participate in WW2 in a military capacity, his book remains full of good information and is perfectly illustrated with diagrams and drawings.
While many of the tactics will not work today (for example, he explains how to derail a train by hitting the fishplates, but modern train lines are one continuous rail now), some of it is still applicable. Moreover we should point out the absolute no-nonsense mentality presented in this book. This manual will teach you how to kill a man silently. It will teach you how to store ammunition for your guerilla cell. It will tell you how to conduct an ambush. And as I mentioned above, it will explain to you and your cell how to derail a train effectively, from start to finish.