I wish I had found this when on active duty. It is one of the best books on the How an extremist organization takes over village after village province after provence. Every SF soldiers needs a copy. Please read it. It was written by an SF officer after serving in Vietnam from 1960-1964 as an USIA project officer than with some combat tours that all in the same AOR in the Mekong Delta. It is communist based but the principles are the same. The ARIS needs to put it on a reading list.
https://www.amazon.com/Village-War-R.../dp/B00B0I5JN4