With the explosion of the Latin population and the popularity of Latin music in this country, it's a wonder no one has written a general book about Latin music yet. Until now, the only one has been John Storm Roberts' The Latin Tinge, which besides being dull and bogged down in detail is out of date.

Which makes The Latin Beat by journalist Ed Morales invaluable. A longtime music critic for such publications as the Village Voice and New York Newsday, Morales does an excellent job of covering Latin music's enormous range, giving us an overview of most of the major strains: Cuban, Brazilian, Colombian, Mexican, jazz, the development of salsa, Latin music's influence on North American music and alternative. It's as up to date as 2003's hottest releases.

Morales makes a powerful case for Latin music as the most vital of American musics, a constantly evolving amalgam of European, African, indigenous and popular influences that can only grow in importance. He balances musicological and historical detail -- repeatedly tying in Latin music's Spanish and African roots and noting which of last year's alternative albums are the most significant -- with a broader sense of what makes Latin music so exciting, how it got to where it is now, and where it's going. He counts out the beat, and most of the time, he lets us feel it too.

For those who of us who write about Latin music or are otherwise involved in it professionally, The Latin Beat will be a useful resource. For those who just like what they hear, Morales offers an easy way to go deeper.

This is a smart history. The focus is on popular music, with the greatest weight going to the genres and traditions that have had the widest impact. Thus the Cuban and Brazilian traditions get the most attention, followed by jazz and alternative, and the various ways that Latin music has influenced American popular music and culture.

Some might argue that Mexico and Colombia, with their rich, complex musical traditions, deserved more attention, but Morales makes a valid case that these countries haven't had the global and popular impact that their sister countries have, despite Colombian star Carlos Vives' success with vallenato and Mexican music's large U.S. sales figures.

Morales' tastes show, and you could argue with some of them. There's probably more space alloted to certain contemporary Cuban bands than their long-term importance warrants. Meanwhile the nueva trova tradition, and its connection to Latin American political movements, hardly gets a nod. Morales can convey the personality of a trend or artist, and the way a sound or song captures the feeling of a moment in pop culture, all essential qualities for writing about popular music. But sometimes his writing bogs down in a dense music critic analysis that, while it conveys information quickly, can be dry and leave the casual reader a bit lost.

Still, these are quibbles in a book that's been a long time coming, and that promises to be relevant for even longer.

Jordan Levin is a Herald arts writer.