FILM: DONALD CLARKEreviews The New Biographical Dictionary of Film(Fifth Edition), By David Thomson, LIttle, Brown, 1,074pp, £35

IN EARLY OCTOBER an unusual explanation appeared above a blog posting an article by David Thomson on the website of the London Review of Books. "The entry on Heath Ledger was inadvertently dropped from the fifth edition of The Biographical Dictionary of Film, out next month," the subheading explained. "It will be included in the sixth edition. In the meantime, here it is."

One can only imagine the mortification at Little, Brown. Since its first edition, in 1975, Thomson's Biographical Dictionary of Filmhas established a (largely deserved) reputation as the slipperiest, most eccentric film reference book on the market. Whereas bumper movie guides such as Halliwell's or Leonard Maltin's have been rendered somewhat redundant by the internet, Thomson's tome remains the sort of book you still want to read in its mighty entirety. Individual entries mesh together to make a surprisingly cohesive, endlessly surprising whole. Ledger's accidental exclusion from such a respected volume will not go unnoticed. Still, Heath will make his appearance in another eight years or so. Won't he?

In his weary introduction to the new edition, Thomson suggests this might not, after all, be the case. After bemoaning the current lack of respect for film writing and noting the sad decline in standards among those movies nominated for the best-picture Oscar, Thomson welcomes us to a book that is “pledged to believing in what was once a mass medium”. He then asks us “not to be too surprised if this is the last edition”.

Raised in England, though long resident in the United States, Thomson is closing in on his 70th birthday. Yet he seems in good health and he continues to churn out books and articles at a prodigious rate. This apparent winding down of biographical operations is, it appears, less to do with concerns about mortality than with a belief that cinema has ceased to matter.

The author's impatience with the medium has been apparent in many of the pieces he has written since the publication of the (greatly expanded) fourth edition, in 2004. Five years ago, writing in The Whole Equation, a maddening, fascinating rumination on Hollywood, he owned up that he now preferred books to films. Last year, introducing Have You Seen?, a superior lavatory book listing 1,000 notable releases, he complained that "too many new films are gestures trying to grab the interest of kids set on war games and PlayStations".

It should, thus, not surprise us that the new and expanded entries are so rarely fired with the enthusiasm that characterises vintage essays on, say, Cary Grant ("the most important actor in the history of cinema"), Jacques Rivette ("the most important film-maker of the last thirty-five years") and Kenji Mizoguchi ("He has no superior in the unfolding of narrative by way of camera movement"). Wes Anderson, for instance – granted just three cheeky lines in the last book – may be "central to the most valuable young generation America has brought to film in thirty years", but the director of Rushmoreand The Royal Tennenbaumsis still treated with a combination of puzzlement and contempt. Unimpressed by the cult attached to Christopher Nolan, creator of The Dark Knightand Inception, Thomson concludes that the English film-maker's work has become "progressively less interesting". His enthusiasm for Paul Thomas Anderson, whose There Will Be Bloodgraces the cover, is only mildly qualified, but that entry still manages to conclude with a reference to this "very threatened medium".

Even without perusing the essays in depth, the reader can, simply by noting who's in and who's not, get a sense that Thomson has become disengaged from contemporary film culture. John Lasseter, creator of Pixar and thus arguably the greatest technical innovator of his age, is rendered breathtakingly conspicuous by his confounding absence. Apichatpong Weerasethakul, the Thai master, winner of this year's Palme d'Or at Cannes, should also be among these pages. Most baffling of all (so much so that one suspects another error in the Ledger mode), Michael Haneke, the most respected serious director of his generation, has somehow failed to make the grade. Only a few years younger than Thomson, Haneke offers, surely, echoes of the golden age for European cinema, running from the late 1950s to the early 1970s, that formed the author's critical sensibilities. What is Haneke's The White Ribbonbut a Bergman film for the digital generation?

The most blazing evidence of Thomson's retreat comes, however, with one of the cheerier new inclusions. The essay on Alistair Cooke, journalist, raconteur and creator of BBC Radio's Letter to America, offers many warm anecdotes about a much-loved figure but fails to explain why, running close to two closely typed pages, his entry is among the longest fresh pieces in the book. Cooke did write about film. That discipline was, however, hardly his main claim to fame. One senses that Thomson feels more comfortable cuddling up to a tweedy icon than engaging with the sharper corners of the modern cinematic machine.

So does the new, possibly final incarnation of the Dictionarycome across as a depressed and depressing entity? To an extent. Thomson is certainly entitled to his ennui – it may even be justified – but one wonders why, so uninterested, he would bother to pursue this fifth edition. The new entries read like the work of a man who would far rather be playing bridge, constructing model railways or doing whatever it is he does when not puffing angrily at Adam Sandler.

Remember, however, that the vast mass of the book was written when Thomson still felt engaged with the medium. The option exists to leave exasperated entries on Keira Knightley and Judd Apatow unread. Alternatively, you could stick with the last edition.

Donald Clarke is the Irish TimesFilm Correspondent