The songs of Stephen Sondheim represent such an ideal marriage of lyrics and music that it is hard to imagine these elements divorced. Still, on its own, Mr. Sondheim’s music is as rich, intricate and ingenious as music can be.


I always enjoy attending great production of a Sondheim musical. But another way to immerse myself in Sondheim’s work is to play through the piano-vocal scores, where I can linger on some pungent harmony, unravel layered contrapuntal lines, slow down a complex rhythmic passage to see how it works, or trace the contours of a beguiling melody.


Mr. Sondheim has no bigger fan than the adventurous pianist Anthony de Mare, a champion of contemporary music. In recent years, merging his passion for Sondheim with his effort to expand the recital repertory, Mr. de Mare has invited composers to write solo piano pieces inspired by a favorite Sondheim song: not just inventive piano arrangements of the songs but new compositions written in the composers’ own styles. Patrons who shared Mr. de Mare’s devotion to Sondheim provided commissioning fees.


The resulting project, “Liaisons: Reimagining Sondheim From the Piano,” has commissioned 36 composers to date. Mr. de Mare has been playing some of these works on a multicity tour this year. He came to Symphony Space on Saturday night for a sold-out concert. There were New York premieres of 17 of these pieces by diverse composers, among them Steve Reich, William Bolcom, Mark-Anthony Turnage (the composer of the opera “Anna Nicole”) and Tania León.


Speaking to the audience about the new works he has fostered, Mr. de Mare emphasized that these pieces were “fully realized creations, not songs without words.”


He opened with a sensitive account of Mr. Bolcom’s tender, short work “A Little Night Fughetta,” which takes the melodies of “Anyone Can Whistle” and “Send in the Clowns” and weaves them together. The modesty of the music masks the ingenuity of Mr. Bolcom’s contrapuntal writing. This was followed by Ricky Ian Gordon’s take on “Every Day a Little Death,” which emerges as a rhapsodic fantasia that jostles elements of rhythm out of their familiar time and meter.


The song “Being Alive” inspired Gabriel Kahane to write a glistening, modernist scherzo that pays double homage to the Sondheim song and to Ligeti’s étude “Désordre” (“Disorder”).


Even when I was not grabbed by one of these reimagined works, it was fascinating to hear how the composer approached the song. In “I’m Excited. No, You’re Not,” for example, Jake Heggie transforms the complex, breathless ensemble number “A Weekend in the Country” (from “A Little Night Music”) into a flashy, finger-twisting showpiece.


During a panel discussion the composer Derek Bermel said that he had found it almost painful to “rip the music” of “Sorry/ Grateful” from its perfectly harmonious lyrics. But he captures the wistful yearning of the original in his subtly brilliant piece, in which harmonies turn spacey, thematic lines leap skittishly across the piano’s register, and the music spins into something of a tizzy at the end.


It was intriguing, if a little disorienting, to hear a composer take an approach to a Sondheim song that was unlike anything I might have imagined. Ethan Iverson’s fidgety response to the ruminative “Send in the Clowns,” complete with cluster chords, fragmented phrases and snarling bursts in the bass register, was a shock. But somehow Mr. Iverson, best known for his work as a pianist with the Bad Plus, a jazz trio, gets at something in this music, and I loved it.


So it continued, with Sondheim songs reimagined, sometimes wildly, by Ms. León, Mr. Turnage, Mason Bates, Paul Moravec, David Shire, Ricardo Lorenz, Fred Hersch, Daniel Bernard Roumain, David Rakowski and Kenji Bunch. Mr. Reich’s perky, insistent take on “Finishing the Hat” is scored for two pianos; Mr. de Mare played one part on tape and the other live. Some of these pieces require formidable virtuosity. Mr. de Mare’s playing was dynamic and stylish, if now and then a little rough.


Mr. Sondheim was interviewed onstage by Mark Eden Horowitz, whose essential book, “Sondheim on Music,” offers in-depth discussions with the composer. After receiving a rousing welcoming ovation, Mr. Sondheim said that though he had been “extremely embarrassed” when the idea was first proposed, he was flattered and thrilled to have his music taken so seriously by so many fine composers.


Mr. de Mare is recording “Liaisons.” Next March, Symphony Space will present Part 2 of the project, with Mr. de Mare performing the other 19 reimagined Sondheim songs. When word gets around, I suspect that more composers will be eager to take part.