In 1989, the Dept. of Energy (DOE) created the Atmospheric Radiation Measurements (ARM) Program. ARM was a highly creative project in which people were given $40M/year and invited to invent a new way of doing atmospheric field campaigns, with an emphasis on clouds and aerosols (the poorest-known components of the global climate system). I was one of ARM’s creators and I have been involved with it ever since 1990 -- till 2005 as a PI on its Science Team, then from 2005 to 2009 as its Chief Scientist. ARM was DOE’s first large-scale entry into a global observational network, and has since grown to be the largest element of its climate program. ARM began as a single super-site in Oklahoma but by the end of the 1990s had added three more super-sites, one in Alaska and two in the Tropical Western Pacific. To pursue a military analogy, these permanent super-sites are like fortresses, which are now complemented by a Cavalry, an Air Force, and soon a Navy. The ARM Cavalry consists of its First Mobile Facility, which since 2005 has been deployed all around the world for 8-10 month periods. The ARM Air Force consists of planes leased from other organizations and bristling with cloud and aerosol instruments; ARM is now experimenting with aircraft deployments lasting 5-6 months instead of the typical one month. The ARM Navy consists of its Second Mobile Facility, just now being built for deployment on large seagoing vessels like car carriers for periods up to a year. This talk will be a whirlwind tour of ARM’s history, interlaced with stories of successes and failures, and projections of ARM’s future as it acquires $60M of new instruments, including the world’s largest collection of cloud radars.