From the site at Trilateral.org:

The Trilateral Commission is a non-governmental policy-oriented discussion group of about 325 distinguished citizens from North America, the European Union, and Japan which seeks to foster mutual issues for which these principal democratic industrialized regions share leadership responsibilities.

A group consisting of world leaders, formed for the purpose of creating a wider international community that fosters cooperation. This commission was founded by David Rockefeller in 1973 as a partnership between private citizens in North America, Europe, and Japan. It has now expanded to include many countries outside of the original 3 locations.

If you look at a list of past and present Trilateralists, it reads like the who's who of the business world. Some of the notable members include former U.S. Presidents and diplomats before they entered their public positions. This commission has garnered much controversy over its existence.