The cause was complications of lung cancer, his family said.
Singing in a soft, lilting voice and accompanying himself on acoustic guitar, Mr. Rankin was often categorized as an introspective singer-songwriter in the James Taylor mold. But he drew inspiration from a wide range of sources: the Brazilian singer João Gilberto was an acknowledged influence, as were Frank Sinatra and Johnny Mathis. And though he wrote a number of memorable songs — his “Peaceful” was a Top 20 hit for Helen Reddy in 1973, and other songs of his were recorded by the likes of Peggy Lee and Mel Torm — he was best known as an interpreter of other people’s.
Mr. Rankin’s albums tended to include a handful of original compositions but consisted mostly of his own distinctly laid-back, gently swinging spin on the Beatles, Bob Dylan and others. In recent years he devoted increasing attention to Cole Porter, Rodgers and Hart and other songwriters of an earlier era.
Mr. Rankin was particularly partial to the Beatles. He recorded a number of their songs, including “Blackbird,” “With a Little Help From My Friends” and “While My Guitar Gently Weeps.” When John Lennon and Paul McCartney were inducted into the Songwriters Hall of Fame in 1987, Mr. McCartney asked Mr. Rankin to represent them at the induction ceremony.