In this introduction to the book CORC: New Tools and Possibilities for Cooperative Electronic Resource Description, editors Calhoun and Riemer set the stage for the book's fourteen articles. The groundbreaking initiative known as the Cooperative Online Resource Catalog (CORC) began in 1999 as a research project in the OCLC Office of Research. The project eventually grew to include several hundred participating libraries. Offering the perspectives of CORC's founders, researchers, developers, library managers and practitioners, the articles discuss CORC's automated tools and experimental practices for finding, describing, and classifying web-based electronic resources of value to libraries and their users. The book was co-published as Volume 4, Numbers 1/2, 2001 of the Journal of Internet Cataloging.