By 1964, Lessing had published six novels, but grew disillusioned with Communism following the 1956 Hungarian uprising and, after reading "The Sufis" by Idries Shah, turned her attention to Sufism, an Islamic belief system. This prompted her to write her five-volume "space fiction" series, "Canopus in Argos: Archives", which drew on Sufi concepts. The series was not well received by some of her readers, who felt she had abandoned her "rational worldview".