Cataloging and metadata services have reached a crossroads. The digital age presents fundamental challenges to building and describing collections of interest to the communities that libraries serve. Since the advent of the Web, what has been fundamental to libraries and higher education, what has constituted professional wisdom and best practice-all have been disrupted by new conditions. This article describes the environment in which libraries are operating and identifies the key trends driving change in metadata creation and management. It also outlines the characteristics of a next-generation metadata creation and management platform for libraries, which the OCLC cooperative is planning, to support future cataloging and metadata practices and the evolution of the expert cataloging community surrounding WorldCat. In Japanese. English version available from author.