2021 publication, US ARMY SPECIAL FORCES INSIGNIA OF THE VIETNAM WAR, THE MAC V SOG RECON TEAMS. The book is hard cover, 420 pages, heavy weight, gloss paper, glued and sewn binding and shows almost 200 different designs of wartime period insignia. Each design is displayed with an original Recon Team member acquired patch along with  period made collectors copies. The book lays out the history of Vietnam period insignia that explains the evolution of Special Forces patches during The War. Each known design is shown along with when each patch was created, who designed them, where the insignia was manufactured, and allot of original pictures of them being worn. It has taken me over twenty-five years to gather this information and if you take the time to read the introduction and study the pictures you should have an advanced working knowledge of the subject.