Every empire or great power, no matter how interventionist it is, undergoes periods of retrenchment. For example, after the Roman emperor Trajan (r. A.D. 98-117) conquered Dacia (Romania) and fought an exhausting, at first successful but ultimately failed war in Mesopotamia (Iraq), his successor Hadrian (r. A.D. 117-138) pulled back. Hadrian accepted defeat in Mesopotamia, gave up part of Dacia, and put the empire on a defensive footing. 

A journalist rather than an academic, Fehrenbach (1925-2013) wrote larger-than-life history of a heroic bent. He is remembered for the bestselling Lone Star: A History of Texas and Texans (1968), whose emphasis on gun-slinging white men now makes it politically incorrect. But he also wrote the sad and beautiful Comanches: The Destruction of a People (1974), which shows great admiration for Native Americans. This Kind of War originally appeared in 1963 with the subtitle of A Study in Unpreparedness and was republished in a new edition in 1994.

Dudley Pope is best known as a novelist who wrote a well-loved series of books about a fictional Lord Nicholas Ramage, an officer in His Majesty’s Navy during the Napoleonic Wars. Pope was also a journalist, writing on naval defense, and he knew the sea. A survivor of a torpedoed merchant ship in World War II, he later lived for over 20 years on a yacht in the Caribbean.