Divine Fury: A History of Genius by Darrin M. McMahon Basic Books, 312 pp., $29.99

Anyone who frequents research libraries in Europe or North America will know that it is not unusual to encounter in them individuals who appear to be rather introverted and yet sport oddly ostentatious hairstyles, with unkempt shocks of hair sprouting with peculiar abandon from their pallid male scalps. You can still encounter the odd Yeatsian dandy, but the slightly disheveled Einsteinian archetype seems largely to have prevailed in the academy, just as the Beethovenian archetype has long prevailed in the world of music. This phenomenon alone, the slightly embarrassing aping of the superficial attributes of genius, reveals an ersatz quality to the idea of genius we have inherited; even in the most solemn temples to intellectual achievement the notion is awkwardly associated with a good deal that is theatrical, preposterous, ridiculous.

Darrin McMahon’s Divine Fury does not shy away from the preposterous and the ridiculous, or from the disturbing and dangerous. Many of us now use the term “genius” as a simple expression of wonder, referring to a person or an achievement that we find inexplicably brilliant. But as McMahon’s rich narrative shows, across its long history the term has accrued connotations that go far beyond this commonsense core, leading us into the realms of superstition, bad science, and subservience to questionable forms of authority. And yet his book ends on an unexpected note of regret that “genius” in the most extravagant sense of the term has given way to more trivial uses, to a culture in which everyone has a genius for something and where even infants might be “baby Einsteins.” The cult of the “great exception,” the unfathomably and inimitably great human being, he tells us, has justifiably waned. Nevertheless, McMahon’s closing words are elegiac, hinting that its loss might somehow diminish us.

In his intriguing story not only is the age of genius dead; the seeds of its destruction were sown very early on. The term “genius” in its modern sense was first adopted in the eighteenth century and it involved a conflation of two Latin terms: genius, which for the Romans was the god of our conception, imbuing us with particular personality traits but nevertheless a supernatural force external to us, and ingenium, a related noun referring to our internal dispositions and talents, our inborn nature. McMahon also details the associations that these ideas had derived from the Greek world, particularly from speculation about the Socratic daimonion, the Platonic idea that poetry is the product of a “divine madness,” and the Aristotelian view that there are fundamental differences between minds.

So why did the moderns need a term like this, in which natural characteristics are fused with supernatural associations? McMahon’s account is not, as we might expect, rooted in the inexplicability of certain human achievements, the perceived inability to comprehend them in purely natural terms. Rather, he suggests that two…