In the eyes of much of the academic establishment, William Bowen and Derek Bok's "The Shape of the River" is the definitive defense of affirmative action. Released in 1998, this book, which was also sponsored by the Mellon Foundation, claimed that racial preferences at America's elite universities were crucial to the growth and maintenance of a healthy black middle class. In this new NAS report, which is titled "The Changing Shape of the River: Affirmative Action and Recent Social Science Research," Russell K. Nieli, a Lecturer in Princeton University's Politics Department, summarizes several studies that directly contradict this and other central claims of the Bowen and Bok book. The research Dr. Nieli summarizes has received little publicity from mainstream media, and is generally unknown outside a narrow circle of specialists. (Contains 31 endnotes.)