The Kenneth P. Dietrich School of Arts and Sciences constitutes the liberal arts core of the University of Pittsburgh, one of the major public research universities in the United States. We provide instruction in natural sciences, humanities, and social sciences for all students studying at the Pittsburgh campus, including more than 10,000 students registered as Dietrich School undergraduates. In addition, the Dietrich School educates 15 percent-more than 1,500-of the University's graduate and graduate professional students, making it the largest graduate program in Pittsburgh. In the summer of 2006, the University's College of General Studies joined the (then) School of Arts and Sciences, expanding the community of learners to include nontraditional students. Students admitted to the program take four core courses in the first two terms of their first year in residence (fall and spring terms). The ''preliminary examination'' in the Department of Chemistry is based on the student's record of performance in these four core courses. The four core courses are selected from at least three of the formal disciplines of Chemistry: Analytical, Biological, Inorganic, Organic and Physical. Two core courses must be taken in an area of concentration selected by the student.