Long before Cole Porter observed that birds, bees and educated fleas do it, the French poet Alexis Piron made the same point in his X-rated “Ode to Priapus.” Anthologized in “The Libertine,” the literary historian Michel Delon’s delectable new volume of 18th-century French erotica, it catalogs an array of fauna (“Dromedary, whale, and duck, / Insect, critter, man”) united in their lusty predilection for verbs and nouns too obscene to print in this newspaper, though collectively identifiable by Porter’s own euphemistic pronoun of choice: “Everything does it, reasonable or not.” Reminiscent, too, of the catalog aria from Mozart’s “Don Giovanni” — an enumeration of the skirt-chasing hero’s thousands of conquests by age, rank, nationality and hair color — Piron’s dirty laundry list underscores both the dogged ubiquity of the sex instinct and the inexhaustible variety of its ­expressions.

Delon’s anthology performs a similar function, displaying the dazzling breadth and depth of the 18th-century obsession with pleasures of the flesh. In the final decades of ancien régime France, an unsentimental, frankly hedonistic brand of thrill-seeking called libertinage — an enterprise in which, according to the playwright Pierre de Marivaux, “one still said to a woman: ‘I love you,’ but this was a polite way of saying: ‘I desire you’ ” — infused every genre from fiction to poetry, theater to philosophy, memoir to popular song (all well represented in short, artfully selected excerpts). It also preoccupied Frenchmen and -women from every walk of life — as Delon emphasizes in his introduction when he compares his book to “a ball attended by seducers and seductresses from all levels of society.”

Certainly “The Libertine” is as lavish — with its sumptuous illustrations of luscious Rococo nudes and other toothsome lovelies — as an 18th-century bal masqué. But Delon’s analogy understates the dizzying diversity of the ball’s invitees. Priapic peasants, depraved duchesses, masked miscreants, sexy sylphs, coy mistresses, foot fetishists, human sofas (!) and a surprising abundance of naughty nuns: These raunchy revelers engage in one decadent mating dance after another, tirelessly chasing “it,” and gamely explaining why it matters.

This being the age of Enlightenment, rationales abound. Some characters, mouthpieces for radical freethinkers like Denis Dide­rot and the Marquis de Sade, extol debauchery as a political statement, a defiant challenge to the oppressive pieties and gross hypocrisies of the Catholic Church. (The word “libertine” derives from libertinus: Latin for freed slave.) Other libertines, empirically oriented philosophes, class the joys of sex among nature’s “most striking phenomena,” as arresting — and morally neutral — as sunsets and moonbeams. Still others, like the jaded, aristocratic roués of Choderlos de Laclos, suggest that the moral bankruptcy of France’s preposterously idle, pampered and self-indulgent nobility is leading nowhere good. Indeed, Delon writes, in 1789 the music finally stopped on our carnal cavorters, and “the revolution swept away this brilliant but corrupted world.” Until it did, though, what a swell party.