The previous reply to your question was colorful, but did not really answer your question. During the French and Indian War, a famous unit of rangers was raised by Captain Robert Rogers to fight hostile Indians and the French-Canadian colonists on their own terms. It was composed of American colonists who were all experienced woodsmen, hunters, and Indian fighters. Their role was to do what British regular troops could not--fight an unconventional war in rugged, heavily forested terrain. Rangers had been raised in the Colonies in previous conflicts, but their role had been largely defensive, patrolling to prevent surprise attacks on frontier settlements. Rogers Rangers operated in conjunction with the British Army, scouting ahead, protecting its flanks from enemy ambushes, and staging ambushes and raids of its own. Rogers was so successful that he was promoted to major and his command expanded to several companies.
The succinct written instructions Rogers issued to his men contained very sound principles for unconventional and covert operations. They deal with such matters as careful scouting, stealth, travelling light and fast, and always seeking to strike the enemy first, hard, and by surprise. Such ideas remain sound today, in spite of all technological change. And they are still taught today in the training program for the elite U.S. Army Rangers.
Robert Rogers was the subject of an outstanding historical novel called "Northwest Passage," written in the 1930's by Kenneth Roberts. The first part of the book was made into a movie of the same name starring Spencer Tracy during the 1940's.