Had Arthur Koestler read Harris's work before writing the Act Of Creation, he might have used it to illustrate that sudden flash of insight he called the "Aha!" factor. Being in a near-permanent state of "Eureka!" is part of the experience of reading Harris. The writer who has been described as the "reigning philosopher of 9/11" offers a virtuoso performance in Civilization and Its Enemies that argues convincingly for America as the sole source of global legitimacy.
The core of Harris's thesis is that civilization reduces the capacity of those it benefits from mustering the will to defend it. "[T]hose who have been long accustomed to the civilized order," he writes, "can no longer remember a time in which they had to wonder whether their crops would grow to maturity without being stolen or their children sold into slavery by the victorious foe." The very concept of "foe" is what we need to recapture, Harris suggests, to defend the civilized world against a rising tide of ruthless barbarism: the task of "those who wish to regard themselves as [being] on the right side of history."
Original thinkers are best described in their own words. The reviewer's temptation to quote at length is held in check only by Harris's tendency to use ordinary phrases in a special sense. When Harris writes "ruthless" or "adolescent gang," he imbues the words with a meaning that would not be ascribed to them in ordinary usage. Quoting Harris without first defining some of his terms could be misleading.
Still, there are passages that outweigh this risk by their ability to illustrate Harris's style as well as his thinking. In a paragraph that describes how some Muslims rejoiced over the destruction of the World Trade Center, he writes that the proportion of such celebrants in relation to the population does not matter. "Any society that can fill even one street with people dancing over the carnage of 9/11 is to be suspected, for it takes much less than a street to pull off such an act."
Appreciating Harris's book is not predicated on agreement with every element of his thesis. He generates ideas at a pace that may not permit him to be always in agreement with himself. His fireworks do more than dazzle, though: they illuminate. This is weighty content in a slim volume.
 MacMillan Publishing Company, 1970.