Secret Mystical and Chassidic societies (Kotzk blog 513)This Episode—based extensively on the research by Rabbi Dr Zvi Leshem—examines several secret mystical societies from biblical times to pre-war Europe, with a particular focus on the secretive group established by R. Kalonymus Kalmish (Kalman) Shapira of Piasecnzo (Piasetzna) (1889-1943). 

Secret mystical circles and societies are not well-known in Judaism, but they have always existed.