Directories are listings of organizations or individuals.
National Center for Charitable Statistics: Serves as "the national repository of data on the nonprofit sector in the United States. Its mission is to develop and disseminate high quality data on nonprofit organizations and their activities for use in research on the relationships between the nonprofit sector, government, the commercial sector, and the broader civil society." (from web site) Includes data plus Form 990's and general background on the nonprofit sector of the economy.
Background and Overview