In 1896, the University of Pennsylvania requested one of its leading African-American scholars, WEB Du Bois to carry out a study of the conditions of African-Americans living in Philadelphia, the capital city of that state. For a year, between 1896 and 1897, Du Bois did a detailed statistical analysis of the lives of black folks in that city.
He went from household to household, interviewing people, finding out how they lived, getting to know their attitudes and prejudices and finally compiling data which, using sociological theories, he analysed and interpreted in the book he conveniently called The Philadelphia Negro: A Social Study.