Former practice of major movie and production studios of requiring movie theatres and TV broadcasting companies to buy and show a set of movies or programming as a whole, rather than being able to pick and choose which movies or programs they wanted to show and buy them separately. Block booking was ruled to be illegal “tying” in a series of United States Supreme Court Decisions between the 1940s and 1960s. These legal decisions ultimately undermined the Hollywood studio system, which dominated movie production from the 1920s to the late ’60s.