A series of fourteen films based on Sir Arthur Conan Doyle's Sherlock Holmes stories was released between 1939 and 1946; the British actors Basil Rathbone and Nigel Bruce played Holmes and Dr. John Watson, respectively. The first two films in the series were produced by 20th Century Fox and released in 1939. The studio stopped making the films after these, but Universal Pictures acquired the rights from the Doyle estate and produced a further twelve films.
The films from Fox had large budgets, high production values and were set in the Victorian era. Universal produced them as B pictures with lower budgets and updated the films' settings to the then-present time of the Second World War, with Holmes fighting the Nazis. Both Rathbone and Bruce continued their roles when the series changed studios, as did Mary Gordon, who played the recurring character Mrs Hudson.
In the 1970s four of the Universal-produced films fell into the public domain when their copyright was not renewed. These four films were restored and colourised. Some of the films in the series had become degraded over time, with some of the original negatives lost and others suffering from nitrate deterioration because of the unstable cellulose nitrate film. The UCLA Film and Television Archive restored the series, putting the films onto modern polyester film, in a process that was jointly paid for by UCLA, Warner Bros. and Hugh Hefner.