A couple of my favorite books in the last couple years are Across the Fence and On the Ground by John Stryker Meyer. John is a Vietnam-era Green Beret. These books are about the cross-border operations conducted by MACV-SOG during the 8-year secret war during Vietnam. MACV-SOG, or SOG for short, primarily operated by sending small teams, usually 6-10, of American SF and their indigenous counterparts. They would operate in Laos, Cambodia, and North Vietnam doing recon, wire taps, POW snatches, etc. along the Ho Chi Minh trail. The stories are absolutely insane. These small teams often engaged against enemy forces numbering hundreds and thousands. Time and time again, they found a way to extract. In large part to the air assets providing cover for them. SOG often used Marine Corps and Army gunships, and the A-1. Very cool to learn how significant this CAS was to their survival. If you are ever at WPAFB for FC1, make sure to stop by the National Museum of the US Air Force because in the Southeast Asia conflict hangar there is some awesome history about this secret war and they actually have some aircraft on display that were in-service providing the support. John Stryker Meyer has also appeared on a handful of episodes of Jocko Podcast where he goes into more detail of these crazy stories.
https://www.amazon.com/Across-Fence-John-Stryker-Meyer/dp/0983256705