Among the brand-name French theorists of the mid-20th century, Roland Barthes was the fun one. (Foucault was the tough one, Derrida was the dreamy one, Lacan was the mysterious one — I like to imagine them sometimes as a black-turtlenecked, clove-smoking boy band called Hors de Texte, with the hit album “Discipline ’n’ Punish.”) Instead of constructing multivolume monuments of systematic thought, Barthes wrote short books built out of fragments. He was less interested in traditional coherence than in what he called jouissance: joy, surprise, adventure, pleasure — tantric orgasms of critical insight rolling from fragment to fragment. He proclaimed the death of the author and advocated a style of reading he referred to as “writerly,” in which readers work as active creators of a text. His critical metabolism ran unusually high: he would flit from subject to subject, defining new fields of interest (semiology, narratology) only to abandon them and leave others to do the busywork. He treated canonical French works with such unorthodox flair it drove conservative professors crazy. (Barthes first rose to prominence, or notoriety, thanks to the furor surrounding his early book about Racine.) In his inaugural lecture at the Collège de France — a sort of mission statement for the most prestigious academic post in the country — Barthes announced that he aspired above all to “forget” and to “unlearn” and proposed, as a kind of motto, “no power, a little knowledge, a little wisdom and as much flavor as possible.”

The most reliable and user-friendly source of Barthes’s special variety of fun — the bouillon cube, if you will, of his critical flavor — is his early book “Mythologies,” originally published in 1957. In it, Barthes basically invented what we think of as cultural criticism: he was the first really first-rate intellectual to tell us what our most mundane pop culture actually means. For decades, however, only part of “Mythologies” was available in English. Its recent rerelease in a new and (for the first time) complete translation gives us an excuse not only to reread the book but also to consider some of the larger questions it raises, nearly 60 years later, for those of us still swimming through pop culture, and in particular for those of us who consider ourselves critics of that culture, which, these days, seems to be just about everyone.

“Mythologies” is, characteristically, less a unified whole than a collection of parts: 53 short essays that Barthes wrote for a literary journal under the rubric “Mythology of the Month.” The column was Barthes’s way of dealing with the explosion of mass culture in the decade after World War II — the rise to omnipresence of a hypercommodified cluster of media (magazines, film, radio, television) that was shaping everyone’s lives on the deepest possible level, like a new form of psychological gravity. In his modest (and non-Newtonian) way, Barthes set out to be mass culture’s Newton: to identify the laws of its behavior, test its stresses, reveal the invisible boundaries of its influence.

Barthes’s basic idea (although with Barthes it’s always dangerous to reduce things to a basic idea) was that the operation of mass culture is analogous to mythology. He argued that the cultural work previously done by gods and epic sagas — teaching citizens the values of their society, providing a common language — was now being done by film stars and laundry-detergent commercials. In “Mythologies,” his project was to demystify these myths. He wrote essays about professional wrestling, celebrity weddings, soap advertisements, actors’ publicity photos, trends in children’s toys and an initiative by the president of France to get citizens to drink more milk. He wrote an essay about Greta Garbo’s face. (“The face of Garbo is an Idea, that of Hepburn, an Event.”) He wrote an essay about Billy Graham, who had come to preach in Paris. (“If God is really speaking through Dr. Graham’s mouth, it must be acknowledged that God is quite stupid.”) He wrote about plastic. (“It is the first magical substance which consents to be prosaic.”)