Written in 1930 by Father Daniel Lord and Motion Picture Herald publisher Martin Quigley, and enforced by the Hays Office on behalf of the Motion Picture Producers and Distributors of America, the Motion Picture Production Code is perhaps the most successful film manifesto of all time, guiding and structuring Hollywood cinema from 1934 until the death of the Code and the introduction of the ratings system in 1968. The constraints of the Code inadvertently developed the metaphors and tropes of classical Hollywood cinema. The Code was adopted by the studios in the first instance as a means of self-censorship to avoid the possibility of state censorship. The Code was revised some eleven times between 1934 and 1961, adding provisions on crime, profanity, and cruelty to animals, among other revisions. It was rewritten in 1966, in a fairly desperate attempt to maintain relevance. This attempt did not succeed, and the Code was, for all intents and purposes, dead by 1967, after changing the face of American cinema. The Code that follows is the modified first version from 1930 that was fully implemented by the Hollywood studios in 1934.