With Aristotle we declare that the ultimate test of understanding rests on one's ability to transform one's knowledge into teaching. Those who can, do. Those who understand, teach. 1
Research begins in wonder and curiosity but ends in teaching. 2
Lee S. Shulman has spent his professional life advocating for the importance of teaching at all levels, from kindergarten through graduate school. He is best known for his theoretical and empirical work on teacher cognition, for his work on the knowledge base of teaching, including the construct of 'pedagogical content knowledge', and for promoting the scholarship of teaching in higher education. After holding professorships at Michigan State University and Stanford University, he currently serves as President of the Carnegie Foundation for the Advancement of Teaching.
Lee Shulman was born and raised in Chicago, the only son of Jewish immigrants who owned a small delicatessen. Educated at a yeshiva high school (that mixed secular with sacred studies), Shulman won a scholarship to study at the University of Chicago.
Throughout his career, Shulman has never lost sight of the importance of subject matter in discussions of teaching. Shulman's interest in the teaching of subject matter and the entailments of different disciplines grew out of his undergraduate education in the College of the University of Chicago with a concentration in philosophy, and later as a doctoral student in Chicago's department of education under mentors Benjamin Bloom and Joseph Schwab. Shulman was particularly influenced by Schwab's notion of the structures of different disciplines-the concepts, traditions and tools that disciplines use to make claims, verify knowledge, and determine the quality of contributions. 3 A literary interpretation is not the same as a scientific proof; the concept of causality in biology is not identical to notions of causality in history. This early introduction to disciplinary difference has proved to be a consistent thread throughout Shulman's career.
Shulman's first academic job was at Michigan State University, where he joined the faculty of education. One of his earliest experiences as an assistant professor involved serving as the recorder for a conference on learning by discovery, a conference attended by luminaries such as David Hawkins, Lee J. Cronbach, Jerome Kagan, Jerome Bruner, among others. Shulman edited the book that emerged from this conference, and credits the experience with first raising his awareness of the wisdom of practice. 4
One of his best-known early contributions arose from his collaboration with a colleague in the medical school, and former college roommate, Arthur Elstein. In a widely cited study, Shulman and his colleagues studied the thinking of expert medical diagnosticians as they engaged in clinical diagnosis. 5 Two themes from this work were to resonate throughout Shulman's later work: (1) the focus on cognition under conditions of uncertainty in professional practice and, (2) the domain-specificity of expertise. Expert diagnosticians did not behave as psychologists predicted or as medical educators taught students to behave. Instead of gathering large amounts of data prior to making a hypothesis, the physicians formed