What is "block booking"

Block booking is a system of selling multiple films to a theater as a unit. Block booking was the prevailing practice among Hollywood's major studios from the turn of the 1930s until it was outlawed by the U.S. Supreme Court's decision in United States v. Paramount Pictures, Inc. (1948). Under block booking, "independent ('unaffiliated') theater owners were forced to take large numbers of [a] studio's pictures sight unseen. Those studios could then parcel out second-rate product along with A-class features and star vehicles, which made both production and distribution operations more economical." The element of the system involving the purchase of unseen pictures is known as blind bidding.