One of the first film trailers appeared in New York in 1913 and was the brainchild of Nils Granlund, an innovative marketing manager for the Marcus Loew chain of movie theatres who went on to become famous as a pioneer broadcaster on radio – and notorious as the producer of risqué Broadway revues. Granlund’s first trailer was for a stage show but he went on to create others for upcoming films, including several Charlie Chaplin comedies.
His idea was seized upon by other moviemakers and cinema owners and soon no film was complete without its trailer. The short films came to be known as trailers because the projectionists originally tended to add them to the end of the reels of the B-movie in a show. Thus they trailed after the supporting movie but came before the main feature.
Answered by: Nick Rennison