It may seem odd to describe the Polish-born philosopher Leszek Ko?akowski as "underrated." After all, he has been the beneficiary of several plum academic appointments, including posts at Yale, the University of Chicago and All Souls, Oxford. Ko?akowski (who is now in his early eighties and lives in Oxford) has also been the recipient of numerous honorary degrees and high-profile prizes, including a MacArthur "genius" award (for once the MacArthur Foundation got it right) and, just a few years back, the Kluge Prize for "lifetime achievement in the humanities," which carries a purse of $1 million (about £590,000).

Not bad for a refugee from Soviet-controlled Poland. But there is an important sense in which Ko?akowski, though handsomely recognised, is still seriously underrated. I do not mean only that he lacks the dubious celebrity enjoyed by Jacques Derrida, say, or Jürgen Habermas, Michel Foucault or even - travelling further down the intellectual food chain - Richard Rorty. I also mean that Ko?akowski's central ideas - ideas that should form an enabling resource for our culture's self-understanding - do not enjoy the sort of public existential traction they deserve.

What are those ideas? First, there is Ko?akowski's devastating anatomy of Marxism, exhaustively put forward in his magnum opus, the three-volume Main Currents of Marxism. It is one of the most troubling signs of the times that Ko?akowski's work on Marxism, even at this late date, should be as pertinent now as it was when it was first published more than 25 years ago. His book drove a stake through the intellectual heart of Marxism. It turns out, though, that he had scotched the snake, not killed it. The opinion columns are even now full of dire prognostications about the death of free-market economics and the revival of Marx's economic fantasies.