Our readers are plenty interested in unidentified flying objects. We know that from the huge response to our front-page Sunday article ... revealing a secret Pentagon program to investigate U.F.O.s. The piece, by the Pentagon correspondent Helene Cooper, the author Leslie Kean and myself ... has dominated the most emailed and most viewed lists since. So how does a story on U.F.O.s get into The New York Times? The journey began two and a half months ago with a tip to Leslie, who ... published a 2010 New York Times best seller, UFOs: Generals, Pilots and Government Officials Go on the Record." In a Pentagon City hotel with several present and former intelligence officials and a defense contractor, she met Luis Elizondo, the director of a Pentagon program she had never heard of: the Advanced Aerospace Threat Identification Program. She learned it was a secret effort ... starting in 2007, to investigate aerial threats including what the military preferred to call "unidentified aerial phenomena." This was big news because the United States military had announced as far back as 1969 that U.F.O.s were not worth studying. A few days later Mr. Elizondo and others there ... announced they were joining a new commercial venture, To the Stars Academy of Arts and Science, to raise money for research into U.F.O.s. I had known Leslie for years, and she told me this looked like a story for The Times. I agreed.