Gordon L. Rottman 
US Army Rangers & LRRP Units 1942 87 [PDF ebook] 

Ranger the very word conjures up visions of small, highly trained units executing lightning-fast raids on an unexpecting enemy. It is also synonymous with high esprit de corps and excellence at arms. The US Army Rangers provide units of well-disciplined soldiers who possess the knowledge and courage to operate on their own, deep behind enemy lines. Gordon L. Rottman explores the history of these unique troops, starting with the original ’Rogers’ Rangers’ company of 1756, whose daring operations and deep penetrations of enemy-held country laid down the pattern for all subsequent Ranger units to follow.