Along with the Vietnam-era "Ranger Handbook" and "Special Forces Handbook", the 1965 edition of Field Manual 31-20 Special Forces Operational Techniques was the bible of the Green Beret of the Vietnam War.
From the Preface: "This manual discusses operational techniques in consonance with doctrine outlined in FM 31-21 which may be used by Special Forces. These methods are applicable to both nuclear and nonnuclear warfare in either unconventional warfare (UW) or counterinsurgency operations. This manual describes intelligence, psychological considerations, infiltration, air operations, amphibious operations, communications, logistics, demolitions, Special Forces field maneuvers, medical aspects and other techniques."
This manual provided operational guidance to Special Forces advisors, MACV-SOG recon teams and other clandestine Allied troops in Vietnam.
Presented in Special Operations Press' distinctive ERDL camouflage cover, denoting a Vietnam-era publication, this 2013 reprint of the 1965 edition of FM 31-20 is an easy to read, 6 x 9 inch, 540 page perfect-bound paperback printed on first quality paper in the USA.