Barbara Cook is no longer the classic inge'nue. The original Marian the Librarian and Cunegonde of "Candide" knows exactly what she's doing with a song. Cook opened a week's engagement at Charlie's last night with a sparkling set of standards, show tunes and pop songs that confirmed the faith of her followers, and introduced many to the joy of Cook-ing.

Opening with a sassy "I Love a Piano," Cook swung easily into a trio of Gershwin greats, including "The Man I Love," a song most singers would save for the climax of their show. But Cook managed to build with each selection.

The singer held the crowd without tricky lighting or snappy stage business, focusing on clear, pure singing. And she knows where the music is coming from--she lovingly identified each composer from Rodgers and Hart to her outstanding composer/accompanist/musical director Wally Harper, who now has three shows running in New York.

When Cook sang "It's Better With A Band," one got the feeling that maybe her voice, like any real gem, is best displayed in a simple setting, in this case, piano and bass. Cook's voice contains all the colors of any band in the land.

Cook knows her songs, and makes sure her audience knows them when she's through. She had the Charlie's crowd laughing at the most subtle lyric twist, holding their breath--and even putting down their forks.