Most means of differentiating higher education institutions emphasize their structural characteristics: faculty size; highest and kind of degree granted; level of external support; size of endowment; number of students; average board scores; admissions selectivity; tuition; and so on. In this article, the author offers a view of differentiating schools that underscores their cultural similarities and differences. In offering a cultural framework of departments and institutions, the goal of this article is to complement, and not to reject, structural frameworks of schools. This work is based on a national study of academics--physicists specifically--sampled from departments at six universities. The present article builds upon the earlier study by more fully elaborating the cultural basis of academic worlds of work, specifying the utility of a cultural classification system of higher education institutions, and detailing how such a system is set apart from prevailing structural means of institutional classification.