Insight Meditation Society (IMS), founded in 1975 by Jack Kornfield, Sharon Salzberg, and Joseph Goldstein, is one of the oldest Theravada-derived vipassana (insight) meditation retreat centers in the West. Located on roughly 400 wooded acres in Barre, Massachusetts, IMS offers residential meditation retreats ranging from weekends to several months. It also operates the Forest Refuge for experienced practitioners and online programming.