American Bar Association
Approximately 370,000 lawyer are members of the ABA, which serves a dual role as advocate for the profession and for the public.

American Economic Association
The AEA has over 22,000 economists as members, which it surveys yearly to gather the consensus of economists on the issues.

American Historical Association
Approximately 15,000 historians are members of the AHA, which promotes historical studies, collects and preserves historical documents and artifacts, and disseminates historical research.

American Political Science Association
Approximately 13,000 political scientists comprise the APSA, which promotes political science research and consultation in academia, business and government.

American Psychological Association
With over 151,000 members and affiliates, APA is the world's largest organization of psychologists. If you're interested in studying the human animal, this is an especially interesting site.

American Sociological Association
With over 13,200 members, the ASA promotes sociological research and policy consultation throughout the U.S.

Ecological Society of America
ESA's 7,000 members conduct research, teach, and work to provide the ecological knowledge needed to solve environmental problems.

National Academy of Sciences
The 1,800 members of the NAS are the top scientists in their fields. Their role is to advise the government on scientific and technical issues, ranging from the hard sciences to the social sciences.

United Nations World Meteorological Organization
The WMO has meteorologists from 179 nations and six territories working to study changing global weather and climate patterns, from ozone depletion to global warming.