Encroaching madness ... the language of advertising, as seen in BBC 4's Mad Men, has been strengthened, not questioned, by Roland Barthes' social science of signs

A little over 50 years ago Roland Barthes published Mythologies, a collection of short theoretical essays, to great acclaim. Mythologies heralded the turning of semiotics - the study of language in terms of signs (made up of signifiers and signifieds) - to the broader horizon of the world and its objects.

Reading the book for the first time as an English student in the mid 90s, drunk, undernourished and bored with both Shakespeare and the Beat generation, I was both fascinated and baffled by Barthes' observations. Here was an established literary theorist who could write about steaks looking like shoes and discuss nostalgia and patriotism in connection with chips.

Almost 10 years later, Barthes coined the phrase "Death of the Author" in his 1967 essay of that title. The main claim is that because the reader, ultimately, has control over the meaning, the idea of authorial intention becomes redundant. But the shift of power in the chain of meaning was not restricted to the literary sphere. As Mythologies showed, awareness of the way in which everyday objects signify also suggests the power to alter this very process. The power, in other words, lies not just with the reader but with the advertiser.

Again, initially I found this a difficult concept to grasp. It is only now, years later, when I return to Barthes sober, nourished and better read that it becomes obvious that not only is the science of signs more widespread, effective and malignant than ever, but so too is the concept of the death of the author. Reading Mythologies now, I take what I want from it. Barthes' ideas are far from redundant - quite the opposite, in fact - but rather than being concrete, in fact act as a gateway to ways of thinking which prove to be even more relevant to this decade than the one in which the book was written and published.

The irony is, in drawing attention to semiotics and our power to alter what, and how, things signify, Barthes didn't necessarily educate the masses as to their own consumerist susceptibility, but in fact alerted new generations of marketing and advertising executives to their power to influence the channels of signification. (Mythologies could almost run as a companion piece to the TV show Mad Men, which considers the ethically questionable myth-makers of the ad world in the advertising boom-time of the early 60s).

Indeed, looking at Mythologies through the lens of contemporary culture, it is depressingly obvious that Barthes' theories, in teaching society about the way it controls its own meanings, actually enhanced and inspired the very world of advertising and marketing that he sought to question and warn us against.

Fifty years on, Mythologies hasn't been superseded, it's been implemented.