NOTICE: The project that is the subject of this report was approved by the Governing Board of the National Research Council, whose members are drawn from the councils of the National Academy of Sciences, the National Academy of Engineering, and the Institute of Medicine. The members of the committee responsible for the report were chosen for their special competences and with regard for appropriate balance.

Support for this study was provided by a grant from the Allegheny Conference on Community Development. Any opinions, findings, conclusions, or recommendations expressed in this publication are those of the author(s) and do not necessarily reflect the views of the organization that provided support for the project.

Cover Photo: The Pittsburgh Point where the Allegheny and Monongahela Rivers converge to form the Ohio River. Photograph courtesy of Jessica Hess. Copyright 2005 by Jessica Hess. All rights reserved.