At the German Embassy Friday, Alan Mandel played Beethoven's last three piano sonatas. Or rather he journeyed through them, inviting the audience to marvel at the music's unique shapes and sounds while passing others by.

This was not the standard package tour. Mandel can be an eccentric performer, taking liberties with tempos and phrasing. While it was often unclear what Mandel was getting at, there was never reason to be bored. The drama of the music -- of sound, phrasing and balance -- commanded the audience's attention throughout this long and demanding program.

As the opus numbers increased, the drama heightened. Opening with Op. 31, No. 2, in D Minor, the "Tempest" Sonata, and progressing to Op. 111's thornier challenges seemed like a wise choice. The more familiar, more accessible work drew the audience right in, while creating the right mood for the late works. Especially wonderful was the way Mandel worked details in. The curious fragments of operatic recitative that mark the Allegro movement's sections took on a magical fascination.

Mandel approached the triple-digit opus numbers with the intensity and curiosity of a child taking apart a watch. To the complex tonal machinery of Op. 110 he brought an approach that was fresh and energetic. The problem with Mandel's unconventional path to Beethoven is that it generates some unconventional technical problems, not all of which have been resolved. The Prestissimo of Op. 109 revealed some glitches in Mandel's articulation. Every pianist's Waterloo, the Op. 111, found Mandel at his boldest and most unmannered. Audience members could almost see the magnificent structure of the Arietta unfolding before them. It would have been nice to see the pianist; the German Embassy should spring for a small stage or platform.