SERENDIP (Search for Extraterrestrial Radio Emission from Nearby Developed Intelligent Populations) is an on-going SETI program conducted by the University of California, Berkeley. It is unusual in being a "piggyback" search, operating alongside conventional radio astronomy observations. Since it began, in 1979, with SERENDIP I, it has undergone three major improvements and upgrades, SERENDIP II (1986–88), SERENDIP III (1992–96), and the current SERENDIP IV.
1. Bowyer, S., Zeitlin, G., Tarter, J., Lampton, M., and Welch, W. "The Berkeley Parasitic SETI Program," Icarus, 53, 147 (1983).