I won't soon forget the experience earlier this year of hearing Loïc Mallié perform the earth-quaking music of Olivier Messiaen on the grand organ of La Trinité, which Messiaen himself played from 1930 until his death in 1992. But, I might never have known about Messiaen's organ music at all were it not for the yearly free holiday performances of his 1935 masterpiece La Nativité du Seigneur: a unique and irreplaceable tradition begun five years ago by St. Thomas Church organist and music director John Scott.

As we near the 100th anniversary of Messiaen's birth in December, Scott has set upon himself the challenge of performing all of Messiaen's organ works over six Saturdays in October and November. (He did a 10-week cycle last year with the music of Dietrich Buxtehude.) The concerts, which ask only for a goodwill donation, range in length from 70 minutes to nearly two hours.

I missed the first part of today's opening concert - a performance of Messiaen's early Prelude, published posthumously in 2002 - but heard all of La Nativité du Seigneur. Scott's fleet-fingered performance was no less stirring than when I last heard him play this work in December.

"The music - which built steadily in complexity and volume until the walls began to shake - was horrible, beautiful, terrifying and ecstatic."

I'm excited to see what Scott does with the rest of the cycle, most of which he has never before performed in New York. Stop by St. Thomas one of these Saturdays at 4pm and hear him for yourself.