The author thanks the many demographers at the Census Bureau and in academe for their contributions over the years to his understanding of historical U.S. decennial census statistics and their limitations, and thanks others, including several high-school history teachers, for their input in developing the Chartbook.  In particular, the author thanks David M. Kennedy (Donald J. McLachlan Professor of History, Emeritus, and Director of the Bill Lane Center for the American West, at Stanford University), Herbert S. Klein (Professor of History and Director of the Center for Latin American Studies at Stanford University), and Alexander E. Landry (Reference Librarian at the U.S. Census Bureau) for their consultation and their support.