Terry Roberts and Laura Billings are the director and associate director of the National Paideia Center (NPC), which provides transformative professional development across the United States and abroad. The NPC is widely celebrated as a primary source for materials and training on classroom dialogue at all levels and in all subjects. Roberts and Billings have written extensively about the relationship between seminar discussion and critical thinking, most recently in their book Teaching Critical Thinking: Using Seminars for 21st Century Literacy. They can be reached through the NPC website or via e-mail at troberts@paideia.org and laura@paideia.org.