John Boyd originally studied fighter pilots in combat, trying to understand why the winners were victorious. Boyd hoped to glean some basic principals that could be taught to future pilots or incorporated into the design of future combat aircraft, so he studied the individual mind of the pilot as well as the aerodynamic aspects of the combat aircraft. The scope of Boyd's studies gradually broadened to that of ground warfare between armies. (This is a gross oversimplification—there are a few thousand pages written about Boyd, his life, and his research).
The military has adopted a lot of Boyd's language and principles in revising modern ground warfare strategies. In the civilian sector, Chet Richards and others have popularized the OODA Loop as a tool for developing corporate strategy.
I have been using the OODA loop process to teach my individual clients how the individual mind works while interacting with their personal environment. When we can understand how our individual mind works, and how to change/reprogram it, we can adapt better to reality.
And, to paraphrase Boyd, when we are better able to adapt, we are more likely to be able to survive on our own terms.