EXPERIENCE MONTEVERDI'S PIONEERING STYLE OF OPERA.

Byline: Allan Kozinn The New York Times

Tracing the evolution of a great composer's style is always fascinating, but there is an extra measure of delight when that development includes the invention of expressive techniques that have retained their power and influence over the centuries.

Claudio Monteverdi devoted himself to giving human passion an unambiguous musical vocabulary. In the bargain, he contributed mightily to the birth of opera and its establishment as a durable form.

`Orfeo': His first opera, ``Orfeo'' (1607), may lack the sophistication and dramatic flexibility of ``Il Ritorno d'Ulisse in Patria'' (1640) and ``L'Incoronazione di Poppea'' (1642), but it has a freshness and beauty that has kept it on the stage, and there is a distinct charm in its careful balance of tragic characterization and formal dance music that reminds us of early opera's idealized, mannered conception of Greek antiquity.

A new recording by Artek, a New York ensemble directed by Gwendolyn Toth (Lyrichord LEMS 9002, two CDs), captures much of the work's vitality and depth, and if it has some shortcomings - a minimal cast doubling on roles, for example - it nevertheless boasts a superb Orfeo in Jeffrey Thomas.