New U.S. Government Manual available online.

"As the official handbook of the Federal Government, the United States Government Manual provides comprehensive information on the agencies of the legislative, judicial, and executive branches. It also includes information on quasi-official agencies, international organizations in which the United States participates, and boards, commissions, and committees. The Manual begins with reprints of the Declaration of Independence and the U.S. Constitution. The new edition of the Manual is available annually in late summer."

Check it out here.