Dr. Richard W. Paul is Director of Research and Professional Development at the Center for Critical Thinking and Chair of the National Council for Excellence in Critical Thinking. Dr. Paul is an internationally recognized authority on critical thinking, with eight books and over 200 articles on the subject. Dr. Paul has given lectures on critical thinking at many universities in both the United States and abroad, including Harvard, the University of Chicago, the University of Illinois, and the universities of Puerto Rico, Costa Rica, British Columbia, Toronto, and Amsterdam. He taught beginning and advanced courses in critical thinking at the university level for over 20 years. He has been the recipient of numerous honors and awards, including Distinguished Philosopher (by the Council for Philosophical Studies, 1987), O.C. Tanner Lecturer in Humanities (by Utah State University, 1986), Lansdown Visiting Scholar (by the University of Victoria, 1987), and the Alfred Korsybski Memorial Lecturer (by the Institute for General Semantics, 1987).Dr. Linda Elder is an educational psychologist and a prominent authority on critical thinking. She is President of the Foundation for Critical Thinking and Executive Director of the Center for Critical Thinking. Dr. Elder has taught psychology and critical thinking at the college level and has given presentations to more than 20,000 educators at all levels. She has co-authored four books, including Critical Thinking: Tools for Taking Charge of Your Learning and Your Life, Critical Thinking: Tools for Taking Charge of Your Professional and Personal Life and Twenty-Five Days to Better Thinking and Better Living. She has co-authored twenty thinker's guides on critical thinking and co-authors a quarterly column on critical thinking in the Journal of Developmental Education. Dr. Elder has also developed an original stage theory of critical thinking development. Concerned with understanding and illuminating the relationship between thinking and affect, and the barriers to critical thinking, Dr. Elder has placed these issues at the center of her thinking and her work.