Rescued Kurt Weill Recording Is Sweet Vindication for Accidental Discoverer OF course he imagined this happening to him. Every collector dreams of it, with every visit to a tag sale or dusty flea market: After years of financial drip-drip-drip, one day you chance across something so rare, so unlikely, that it makes all the other searches worthwhile. When it happens - when you find the heretofore unknown recording by a major composer, in a cardboard box on the Upper West Side, a rejoinder to all those loved ones who consider your collecting a little, shall we say, impractical - you float to Hawaii on a chocolate sunbeam, right? For Guy Walker, it did not work out that way. "I was scared," Mr. Walker, an artist and a collector, said the other day, sitting in his apartment in Chelsea, beginning a circuitous tale of discovery and stewardship. I still am. This is a responsibility. Things break. I'm afraid the damn building will burn down. I'm a borderline paranoiac. I said: Someone's got to take this off my hands. This is too important for some schmo to have. Mr. Walker has, as you might expect, a story. In 1978, as a young blues fan living in Essex, Conn., when his peers went off to college, he left for a different kind of education, in the East Village and at the Art Students League. Mr. Walker, 54, gets excited when he talks about the blues, Avenue A, punk rock, neoclassical artisanship, Robert Schumann, motorcycle movies, defunct used-book stores and much else. But he especially got excited describing the day in 2007 when, at the prompting of his friend Dave from Detroit, he answered an ad on Craigslist offering old books and records for sale and found four 78 r.p.m. acetate discs of a Kurt Weill work that even Weill scholars did not know had ever been recorded. The find, it turned out, was just the start. "This has not been fun and games," Mr. Walker said. This has been five years. To begin at the beginning: In 1939 and 1940, the World's Fair in Flushing Meadows, Queens, included an elaborate pageant, "Railroads on Parade," for which Weill, a refugee from Nazi Germany, composed the music, sewing together American folk songs with his own original orchestrations. For four or five performances a day, thousands of fairgoers paid a separate admission price to see the hourlong pageant, which featured actual trains onstage, along with 100 costumed performers who pretended to sing, while the actual singers and musicians belted out the numbers into microphones in a sound studio under the stage. More than two million people saw the extravaganza, the largest audience for any of Weill's works in his lifetime, according to Kim Kowalke, president of the board of trustees for the Kurt Weill Foundation for Music. When the fair closed, the music disappeared, never to be heard again. The score survived, but for decades, no one performed it or published it, except for one song. Documentary film clips of the pageant were silent. There were no known recordings of the work. Enter, 67 years later, the accidental discoverer. For Mr. Walker, who lives with his partner, Jeffrey Peabody, vice president of the Matthew Marks Gallery, in an apartment where all records and stereo equipment are hidden from view, there is nothing quite like the sound of old 78 r.p.m. discs: the quality of microphones used in their recording, the metal in the wires all produced a sound unlike any that has followed it. After he acquired a taste for classical 78s, he said, "I started collecting everything I could get my hands on," storing most of his collection in two lockers in the basement. When his friend Dave led him to the sale on West 85th Street - "They said somebody had died in the building," Mr. Walker recalled - he was only mildly intrigued by the pickings. There was an incomplete set of Schumann, and another folder with four discs with Weill's name on them. "I figured they were recordings of a student singing," he said. You find stuff like that a lot. He paid about a dollar a disc, the usual for such transactions, he said. "Who wants classical 78s?" he said. It wasn't a major haul. But when he got home, he started searching online for information about the composition "Railroads on Parade," which he had never heard of. There were descriptions of the pageant at the fair, but no mention of any recordings. He realized he had found the grail: a recording that did not appear to exist anywhere else. "This was just so out of the realm," he said. You don't think you're going to find lost historic recordings. He contacted the Weill foundation and Weill scholars, and learned more about the music and the fair. "The fair had its own radio station," said Bruce D. McClung, who is writing a book about the music at the 1939 and 1940 fair, which included original works by Aaron Copland, George and Ira Gershwin, William Grant Still and others. The four discs Mr. Walker found were probably made for a broadcast from the fairgrounds, Mr. McClung said, though it was impossible to tell whether they were ever broadcast.