ESL Incorporated, or Electromagnetic Systems Laboratory, was a subsidiary of TRW, a high technology firm in the United States that was engaged in software design, systems analysis and hardware development for the strategic reconnaissance marketplace. Founded in January 1964 in Palo Alto, California, the company was initially entirely privately capitalized by its employees. One of the company founders and original chief executive was William J. Perry, who eventually became United States Secretary of Defense under President Bill Clinton. Another company founder was Joe Edwin Armstrong. ESL was a leader in developing strategic signal processing systems and a prominent supplier of tactical reconnaissance and direction-finding systems to the U. S. military. These systems provided integrated real-time intelligence.