Many US universities have for decades run first-year courses entitled, with slight variations, 'Western Civilisation'. The idea behind them was that all students needed some grounding in the intellectual and cultural foundations of 'our' way of life. Even budding physicists and dentists had to sit, often bored, through a crash-course in the 'great thinkers and great books' of a western – essentially western European, then north American – tradition. The purpose was as much nation-building as it was educational, since the children of new immigrants were thought especially in need of such civilisational induction. The education systems of European countries rarely felt the need for that kind of teaching. From the late 60s, and more fiercely from the 80s, 'Western Civ' courses and the thinking behind them came under attack. They should, it was urged, be replaced by something more planetary or (in what was presented as, but of course wasn't really, a synonym) more multicultural. The changes which ensued were often in reality pretty minimal: adding a few token 'Eastern' thinkers to the 'Great Books' list, a black woman novelist or two, plus a vague bow to the richness of African or Native American traditions. What the revised versions presented was not a truly global perspective, but just a slightly broader range of ways of being American. Cultural conservatives, nonetheless, saw such changes as wildly radical, even nihilistic assaults on 'our' civilisation itself. Their counterattacks launched what came rather pompously to be labelled the 'culture wars'.

After September 2001, though, that war of words seemed totally overshadowed by a more nakedly political, and physical, sense of confrontation. The Islamist attacks on America prompted ever more febrile rhetorics of the 'war on terror' either as defence of civilisation or as a 'clash of civilisations'.

Very little in the language, or the underlying attitudes, here was new, even if they were now more widely and heatedly deployed than before. Roger Osborne is surely wrong to suggest that the concept of civilisation had been left to "lie comfortably undisturbed" for decades before 9/11, and that only recent events "have brought this vague notion suddenly into the foreground". Such claims simply make his vast project sound more novel, more urgently timely, than it is. For in reality Osborne's book is, across nearly all of its great length, a very traditional and conventional metahistorical sketch of 'western' history. It might almost have been designed as a textbook for one of those good old-style US Western Civ courses.

For that kind of purpose, it does in the main a very decent job. It is lucid and accessible in style, if not exactly sparkling. It's based on impressively wide reading – even if the choice of sources becomes more haphazard or sometimes idiosyncratic the nearer it gets to the present. If one wants, say, an introductory survey to the main currents in ancient Greek philosophy, then Osborne's Civilisation offers a very clear and competent one. It is factually reliable: though there's a scattering of minor errors, perhaps inescapable in a work of such broad scope, especially again when dealing with the more recent past. To take a few examples almost at random: the account of early English radical politics is riddled with small mistakes, and (for serious trivia buffs) the murder at Altamont in 1969, symbolic death of sixties hippie optimism, didn't take place while the Rolling Stones were playing 'Sympathy for the Devil' as Osborne says. However metaphorically neat that would have been, it was actually the more banally sexist 'Under My Thumb' which served as soundtrack for the killing. The trouble is, Osborne and his publishers want to claim that Civilization is not a general, rather textbookish historical survey, but something quite different and far more innovative: a sweeping new interpretation of the very idea of civilisation, apt for the (supposedly) wholly transformed world we inhabit since 9/11.

A more tightly focused history of the idea of civilisation, tracing its transmutations across the centuries and placing recent rhetorics of struggle and defence in that context, might bring one closer to those declared aims. More specialist historians of ideas have indeed been attempted variants on that task, but Osborne barely engages with them. Equally, he bypasses all those writers of recent decades, from Fernand Braudel to Chris Bayly, whose attempts to write truly global history call into question the very idea of 'the west'. Is, for instance, the Islamic tradition part of 'western culture'? Osborne's unshakably North Atlantic perspective simply assumes it isn't. The view from China or India might be rather different. Conventionally enough, he places the crucial origins of Western Civ. in Athens – but where then is Jerusalem, or indeed ancient Egypt? Martin Bernal's famous claim that the roots of Greek culture lay largely in Egypt may be (indeed, in my view, probably is) mostly wrong, but it seems odd not even to mention the argument. Even when suggesting that "the later adoption of Greece and Rome as our cultural ancestors has obscured the story of what actually happened", Osborne doesn't follow this up with any significant revision to the old, standard story.

The main puzzle this book prompts is why, today, anyone should have wanted to expend such enormous, and in itself admirable, effort on retelling such a traditional tale.