Many artists put out commercially viable, little-effort-required Christmas CDs. Sarah McLachlan is not one of those artists. Wintersong is not one of those CDs.

Despite its line up of Christmas carols -- "O Little Town of Bethlehem," "Silent Night," "Have Yourself a Merry Little Christmas" -- Wintersong feels more wintry than Christmasy, more bittersweet than exuberant. It is as wholly unsuitable for a rowdy Christmas party as it is for a round of mall-hopping. If you require your holiday music to be along the lines of "Frosty the Snowman" as sung by chipmunks, by all means, avoid this recording.

McLachlan's gorgeously expressive voice and an underlying thread of loss and yearning tie the 12 tracks of Wintersong together to form a delicate and introspective CD for the season. Forget those chestnuts roasting on an open fire; this CD captures the exquisite ache of being alone during the holidays, of coming home to a dark and empty house when everyone else seems to be celebrating. Play Wintersong by a dying fire on a cold December evening. Play it on a sultry afternoon in July for a breath of crisp, cold air. Play it any time of the year, except on Christmas morning when a little more yuletide cheer is called for. Then you can pull out the Chipmunks.

Only the title cut is an original composition; the rest range from covers of Diana Krall's "Christmas Time is Here" and Joni Mitchell's "River" to a selection of rather plaintive traditional pieces. The CD starts with its weakest track, a slavishly faithful cover of John Lennon's "Happy Xmas (War is Over)" that does nothing for the song or McLachlan's voice.

It gets better. I'm not familiar with the original version of "River," but McLachlan's is fragile and poignant in its regret over a past lover. "Wintersong" is even more eloquent about its sense of loss. Simple piano chords form the background against which McLachlan croons, "I lie awake and try to recall how your body felt beside me ... Oh, I miss you now, my love. Merry Christmas, merry Christmas, my love." With its warm, layered vocals, understated guitar and wistful lyrics, "Song for a Winter's Night" is another easy favorite. Listen to any of these in the right mood, and they will bring you to tears.

McLachlan's traditional carols are, for the most part, similarly low key. "I'll Be Home for Christmas" is slow and appropriately sentimental, embellished with an ambient electronic background and a mellow sax solo. Crystal clear vocals give "The First Noel/Mary Mary" an initially orthodox sound, but the song soon develops an exotic and powerful rhythm. How tribal drums manage not to jar with the rest of the CD I can't begin to guess, but they don't.

Actually, I love every song after the first, and even that's more bland than bad. The CD ends with "Christmas Time is Here" whose cheery lyrics are given an ironic twist by their melancholy delivery and stripped-down piano accompaniment.

McLachlan's Freedom Sessions is one of my favorite CDs of all time, and although more electronic and polished, Wintersong captures some of the same emotions. It probably won't make you happier, but it's the perfect soundtrack for indulging in a contemplative and solitary mood.