The phrase "teachable moment" has a taken-for-granted connotation of readiness to learn, but has been rarely defined and researched in the literature of higher education. This study described faculty members' experiences of teachable moments in their undergraduate classrooms. This included the conditions in which they emerge, and the decision-making processes used by faculty members to determine if and how to pursue such moments. If professors have opportunities to clarify their understandings of such moments, the ability to capitalize on otherwise unplanned teaching opportunities may be enhanced. Seventeen experienced social science and humanities faculty members teaching undergraduate classes at a large research university participated in two semi-structured active interviews (Gubrium and Holstein, 2003). The interviews addressed their understandings of, experiences with, and decisions about teachable moments in the classroom. These interviews yielded descriptions of teachable moments as creating a heightened sense of engagement and interaction about a topic of shared interest. Teachable moments fall along a continuum of predictability, with some moments being intentionally designed by the professor and others emerging spontaneously during a class vii as a result of current events or student comments. When confronted with surprise moments professors consider a complex set of interacting elements to decide whether to pursue or postpone the exploration of the moment. They ask themselves several questions. Is there time? How does this fit with goals for the class, course or program? Are the students and I ready to examine this? What impact will this have on classroom dynamics? Does this warrant in-class exploration, or should it be pursued outside of class? The set of considerations can be examined as manifestations of Schon's (1987) theory of reflection-in-action which describes how professionals make decisions in surprise situations when previously effective responses do not work, and more specifically of Steier and Ostrenko's (2000) adaptation of Schon's model, reflection-in-interaction. Implications for theories and practices of teaching of college teaching as well as for opportunities for faculty development were described. [The dissertation citations contained here are published with the permission of ProQuest LLC. Further reproduction is prohibited without permission. Copies of dissertations may be obtained by Telephone (800) 1-800-521-0600. Web page: http://www.proquest.com.bibliotheek.ehb.be/en-US/products/dissertations/individuals.shtml.]