Looking for Leo. Must have strong sense of fun

Thinkers," Marcel Gauchet, the political writer and editor of the French magazine Le Débat , has said, "are never keen to reflect on that which enables them to think." The concepts and categories of the thinker's toolkit are grabbed for a purpose - the ideological monkey wrench, the theoretical Rawlplug. They are seldom inspected for their own truth and beauty. Stoic as it may be, the Rawlplug leads a resolutely unexamined life. The history of the monkey wrench, however, has now been written. The Cambridge History of Twentieth-Century Political Thought offers itself as a kind of compendium reflection on the whole kit and caboodle - bit by bit, ism by ism - hatched, batched, matched and despatched in 28 tightly plotted chapters.

It begins with "The coming of the welfare state" (Michael Freeden) and ends with "The grand dichotomy of the 20th century" (Steven Lukes). In between it takes in nationalism and imperialism (James Mayall), fascism and racism (Stanley Payne), conservatism (Noël O'Sullivan), socialism and social democracy (Dick Geary), Asian communism (David McLellan), western Marxism (McLellan again), existentialism (Sunil Khilnani), positivism (Melissa Lane), utilitarianism (David Miller and Richard Dagger), pacifism (Martin Ceadal) and feminism (Susan James), not to mention the small matter of modernism (Walter L. Adamson) and postmodernism (Peter Dews). It also takes in a number of things that are not so conveniently labelled, for example "The advent of the masses and the making of the modern theory of democracy" (Richard Bellamy) and "Weber, Durkheim and the sociology of the modern state" (Antonino Palumbo and Alan Scott), together with quicksilver congeries such as identity politics (James Tully) and green political theory (Terence Ball). The task in hand is succinct exposition laced with perspicuous evaluation. In their own terms, most of the contributors succeed admirably. Some produce incisive models of compression (Miller and Dagger, and Ball). Remarkably few succumb to involution or idiosyncrasy.

The project itself invites further scrutiny. The CHTCPT is a mammoth undertaking, immune to happy acronym. At a cover price of £95.00, no one will buy it. (Which is to say, only institutions will buy it. And some of them will think twice.) Worse, no one will read it. It is not a book to be read. It is a book to be raided, or, more politely, consulted - "a major work of academic reference", as the dust jacket solemnly proclaims. The publishers boast that "it provides a comprehensive overview of the development of political thought from the late 19th century to the end of the 20th century". The editors call it "an overview of the main currents of social and political thinking". In a commendably honest introduction, they acknowledge that this volume, like the series of which it forms the concluding part, deals primarily with western political thought ("western" because they wish to make the point that cross-cultural transmission has called into question that very designation). There are tailpieces here on non-western political thought (Bhikhu Parekh) and Islamic political thought (Salwa Ismail), but the addendum-like presentation and almost complete segregation tend rather to marginalise and ghettoise these contributions.

The non-West is perhaps an entity more deserving of inverted commas than its off-the-peg "Other". From the cloud-capped towers of Cambridge, it appears less thought than after-thought.

The editors themselves broach the issue of comprehensiveness or capaciousness - the scope of "the political", as they put it, and the construction placed on "thought". For Heidegger, according to one of his closest confederates, "there was certainly more thought in one Braque still life than in 500 pages of Sartre". This was something more than a put-down of Sartre. In his own late work Heidegger turned poet, ruminating suggestively on the profound question raised by his engagement with art in general and with Cézanne and Braque in particular, the relationship between poème and pensée , art and thought:

In the painter's late work, the difference/ of what enters the presence and the presence itself/ is joined in simplicity; it is "realized" and/ at the same time handed over to itself,/ transformed into the identity of an enigma./ Does a way open here, that would lead to a common/ presence between the poem and the thought?

Questions such as this are not addressed in the CHTCPT . Possibly they are assessed as falling outside its scope. Yet room has been found for an unenlightening essay on "Modernism in art, literature and political theory" (Adamson), and even one on "Freud and his followers" (Paul Roazen), which is not very helpful on Freud or his followers, though it does posit some intriguing intellectual genealogies (Sigmund Freud-Graham Wallas-Walter Lippmann).

There are other absences, and absentees. International political thought hardly registers. Except on the environment, the CHTCPT is deaf to the discourse of global politics. Globalisation itself musters but one glancing reference. There is no mention of such classic tropes of 20th-century political thought as deterrence, appeasement or containment. A mite more technically, the editors open with a graceful nod to "the hermeneutics of suspicion" (a suspicion of taking anything at face value, not least histories of political thought), but within these pages, it is nearly impossible to establish what hermeneutics is (are?), except that there is (was?) "a new science of hermeneutics" elaborated by someone called Dilthey, "which could interpret social facts and cultural artefacts by grasping their specific meanings" - the specific meaning of which is a little elusive - and that this was decidedly opposed to positivism.

Dilthey, Wilhelm (1833-1911), figures among the omnium gatherum potted biographies at the back of the book, as one of the founders of hermeneutics, "a theory of interpretation which emphasised the historicity of texts and the role of language in the human sciences", which leaves it still marvellously unclear.

Anyone who believes that ideas of this sort cannot be reduced to thumbnail clarity without wholesale vulgarity could sample a major work of academic reference from the other place, The Oxford Companion to Philosophy (£30.00), masterminded by Ted Honderich, which has model mini-essays on many of the knottiest problems encountered here, including hermeneutics, or for that matter The New Fontana Dictionary of Modern Thought (£15.99), edited by Alan Bullock and Stephen Trombley, which throws in culture-jamming, post-colonialism, fetishism and fuzzy logic for good measure.

Turning from knotty problems to nutty professors, the CHTCPT is not much more consulter-friendly. If a student of the fin-de-siècle political jive wants to investigate the intellectual roots of the "Leo-cons" in Washington, that is to say the self-confessed acolytes of the political theorist Leo Strauss, she will find seven references to the man himself in the name index. From these, she will gather what he was against (scientism, relativism and behaviourism), but not what he was for. She will pick up a tingling allusion to "the most dangerous proclivities of democracy", and a ritual assertion that his teaching was indeed influential. She will fail to discover any explanation of the allusion or the assertion. According to the potted biography of Strauss, "he exerted a profound influence over such thinkers as Walter Berns, John Porter East, Dante Germino, Henry V. Jaffa, Willmoore Kendall and William F. Buckley Jr". Chagrined to find that she has heard of only the last of these - and doubtful whether he is much of a thinker - she may turn again to the index, only to draw a complete blank until she alights on Buckley, founding editor of the National Review , who is said to be "sympathetic to both the market and religion", which seems at once cryptic and unremarkable.

Finally, the dogged student may wish to do some further reading. Locating Strauss in the bibliography proves surprisingly difficult, because it is divided into several parts, each part sub-divided into "primary sources" (the texts themselves) and "secondary sources" (subsequent commentary), a classification simpler to state than to operate.

There is a further lead to pursue. Strauss taught at the University of Chicago. So did others. The connection is another blank spot. "The Chicago school" makes a fleeting appearance, again unexplained. Nothing is made of the famous Committee on Social Thought, a phenomenon almost as interesting in this context as the Institute for Social Research at Frankfurt, popularly known as the Frankfurt school. The Committee on Social Thought was at one stage chaired by Saul Bellow, whose day job or vocation was to write the Great American Novel. Which brings us back to art and thought. In Bellow's novel Herzog , mad Moses Herzog interrogates the elders by writing letters: to Nietzsche ("My dear sir, may I ask a question from the floor?"), to Teilhard de Chardin ("Dear Father... Is the carbon molecule lined with thought?"), to Heidegger ("Dear Doktor Professor... I should like to know what you mean by the expression 'the fall from the quotidian'. When did this fall occur? Where were we standing when it happened?"). Here, perhaps, is a hint of the missing ingredient. Whatever the merits of the CHTCPT as intellectual inquiry, it is not much fun. "Would Kant have been a better philosopher," the poet Charles Simic asks anarchically, "if he had worried about sausages as much as he did about the critique of pure judgement?"

Alex Danchev is professor of international relations, Keele University.