Too often, teachers scratch their heads and ask, "What were my students thinking?" then answer, "I don't want to know." But teachers should want to know, and students should question their own thinking, as well. Critical thinking involves not just problem solving, creativity, analysis, and synthesis but also self-awareness of learning and learning strategies. This article offers instructional strategies that teach students to think critically. Fostering critical thinking requires shifting from a teacher-centered classroom to a critical thinking-centered classroom. This involves relinquishing the role of a teacher as the sole disseminator of knowledge and structuring lessons to allow for student inquiry, research, and collaboration. By providing students with inquiry-based, engaging, rigorous, real-world content and teaching them to monitor their own learning, schools can create a generation of learners capable of solving the problems of the 21st century. (Contains 2 figures and 1 online resource.)