In “A Complete Unknown,” Timothée Chalamet does his own singing and playing on guitar and harmonica — after five years of studying to master the music of Bob Dylan.

One of the most versatile harmonica players in pop history is Stevie Wonder, shown here in Paris in 1963 at age 13. Charley Ley / Mirrorpix Many harmonica histories begin around 1100 B.C. with the ...