In fact, beginning in 2011, Mr. Gates met with Mr. Epstein on numerous occasions — including at least three times at Mr. Epstein’s palatial Manhattan townhouse, and at least once staying late into the night, according to interviews with more than a dozen people familiar with the relationship, as well as documents reviewed by The New York Times.

Employees of Mr. Gates’s foundation also paid multiple visits to Mr. Epstein’s mansion. And Mr. Epstein spoke with the Bill and Melinda Gates Foundation and JPMorgan Chase about a proposed multibillion-dollar charitable fund — an arrangement that had the potential to generate enormous fees for Mr. Epstein.

“His lifestyle is very different and kind of intriguing although it would not work for me,” Mr. Gates emailed colleagues in 2011, after his first get-together with Mr. Epstein.