The Encyclopedia of Popular Music, edited by Colin Larkin

Marathon set of a one-man band

For many people, popular music began in the 1950s, when Bill Haley invited us to "Rock around the clock" and DJ Alan Freed coined the phrase "rock'n'roll". Others would cite Frank Sinatra, with his hordes of screaming 1940s bobby-soxers. For Colin Larkin, popular music began around 1900, the golden era of Tin Pan Alley in New York, where the young George Gershwin would soon begin his career as a song-plugger.

So he has more than a century of music and musicians to cover - a span far shorter than The New Grove Dictionary of Music and Musicians, for sure. Larkin surveys a field where definition, always difficult, is now complicated by the way in which new acts are launched (the Arctic Monkeys via the web) and music consumed (increasingly via digital download). Should those whose career has yet to stand the test of time merit entry into a serious reference set intended as popular music's own New Grove?

Grove editors seemed befuddled: the last edition, published with the new millennium, included more popular-music entries than ever before. There, Wilfrid Mellers, a classical musicologist who once scandalised colleagues with a book about The Beatles, and semiotician Simon Frith made the decisions as to who made the cut and who didn't, though in many cases (and I was a contributor) their rationale was unclear. Larkin works virtually single-handed, and is to be congratulated on his achievement, but one feels that he often can't separate wood from trees.

The line between so-called "popular" and so-called "classical" music used to be clearly drawn, although that wasn't necessarily a good thing. But phenomena such as the Three Tenors and Classic FM have so comprehensively blurred it, and marketeers so shamelessly exploited that, it sometimes seems as if all but a few artists defy categorisation. That Gershwin, Bernstein and Sondheim feature in Larkin's set is easy to understand, for each self-consciously drew on non-classical traditions. But Franz Lehar, who composed The Merry Widow? His roots lie somewhere else entirely.

A better case might be made for the inclusion of Gilbert and Sullivan, for the harmonic banality of their work has much in common with many pop songs - but they aren't covered. Why is Arvo Pärt in and, since he is, why not Górecki? Why Domingo but not Pavarotti or Carreras? Why not Lesley Garrett? Why is Ken Russell's biopic Lisztomania accorded its own entry - because it starred Roger Daltrey, Rick Wakeman and Ringo Starr? So why not Ned Kelly, which featured Mick Jagger? Definitions destroy (as Dylan said), but definition and focus are needed if something as vast as popular music is to be tackled in this way.

Apart from anything else, Larkin's Encyclopedia already runs to 10 volumes. True, future editions are likely to be published online only, but even then there must be a danger they become unwieldy. Meanwhile, the cost of the set puts it beyond the reach of all but the most moneyed fans - although Omnibus Press will publish a one-volume concise edition, at £39.95, in June. And whatever its extent, best use needs to be made of the space; frequently, it's not.

Entries are laced with the sort of incidental detail that has no place in an encyclopedia and the writing can be sloppy, the judgements subjective and juvenile. Both Lennon's Plastic Ono Band album and his sense of humour are "brilliant", and he is "suddenly brutally murdered". Nana Mouskouri is, inevitably, "a bespectacled vocalist", but no mention of her scholarship to the Athens Conservatoire, from where she was expelled for the heresy of singing jazz, nor of Harry Belafonte's crucial role in bringing her to an American audience.

The musical Piaf is accorded more space than "Piaf, Edith", whose entry is shorter than Olivia Newton-John's. Why dedicate six column inches to the musical Bernadette, a "bizarre and spectacular" failure, which closed after three weeks with losses of £1.25m?

Many inconsistencies remain to be addressed. There is (rightly) a lengthy entry on the blues and a much shorter one on reggae, but nothing for gospel. Ska and salsa are included, but not tango or ragtime. The Newport Jazz Festival is in, but not its Folk counterpart.

There's the Cavern and CBGBs, the New York club where punk was nurtured, but not Gerde's, important in the career of Dylan among others. Perhaps none of those should be included, which would leave more space for the world music that Larkin admirably seeks to cover. His discographies should list only original releases and those compilations containing previously unreleased material, all without the highly subjective star ratings; bibliographies should be selective.

For too long, popular music has struggled to be taken seriously. Colin Larkin's work is an important step in the right direction, but such an undertaking needs to be critical at least as much as comprehensive. Otherwise, it is the written equivalent of one of those overblown 1970s double albums.

Liz Thomson is, with David Gutman, the editor of critical studies of Lennon, Dylan and Bowie (Da Capo Press)