Why did Priestley set his play in 1912?

Priestley set his play "An Inspector Calls" in 1912 to highlight the social and economic conditions of the time, particularly the class disparities and lack of social responsibility prevalent before World War I. This temporal setting allows him to critique the attitudes and values of Edwardian society, contrasting them with the post-war awareness of social interdependence. By using this period, Priestley underscores the need for social change and the dangers of ignoring collective responsibility, making the play's themes resonate even more strongly in the context of the play's premiere in 1945.