According to the Internet source given below, John Langstaff was an American concert baritone, musician, educator and early music revivalist of the of Christmas Revels (a Northeast United States tradition.
He studied at the Curtis Institute of Music and the Juilliard.
Langstaff's lifelong project, the Christmas Revels, began in 1957. His life and work with the Christmas Revels is chronicled in To Drive The Dark Away
, a documentary film by David Nath.
||Biography by wikipedia.org.