I acknowledge some debts, old and new, in the writing of the second edition of my book for social studies teachers. In particular, I thank my wife, Iris, a front-line secondary social studies teacher, for her confidence in me and for her many suggestions that sprang from a realistic sense of what can be achieved with young people in the classroom. I also owe a debt to my mentor and teacher, Byron G. Massialas, who set me on the path of social studies education some years ago. My students deserve special thanks and an honorable mention because they taught me a great deal about clarity, specificity, and meaning in creating lessons for secondary students. Their valuable suggestions, and recognition of errors helped shape the new edition. There are also many colleagues, scholars, and experts from whom I borrowed or adapted ideas and to whom I owe a deep sense of intellectual gratitude. Finally, my editor, Naomi Silverman, deserves kudos for the encouragement and personal assistance given me during the development of Social Studies for the Twenty-First Century, and toward the rewriting of this, our second edition.