The American Institute of Physics celebrated its 90th anniversary this year.
AIP was first founded primarily as a publisher and an alliance of the American Physical Society, Optical Society of America, Acoustical Society of America, American Association of Physics Teachers, and the Society of Rheology. In the intervening decades, it has expanded to 10 member and 27 affiliated organizations, including over 100,000 individual members.
In addition to its ongoing publishing mission, AIP hosts professional development webinars, promotes the study of physics and the history of physics, and engages with public policy on science.
You can read more about the history and 90th anniversary in Physics Today.