This is the astonishing story of Sabbatai Sevi, 17th-century rabbi, Kabbalist and probable manic depressive, who convinced large numbers of Jews throughout Europe, the Middle East and North Africa that he was their long-awaited Messiah. And then, on threat of painful death from the Turkish Sultan, apparently converted to Islam and in so doing created the strange Donme sect - outwardly Muslim, yet clinging secretly to Sabbatai's strange form of mystical Judaism - a sect that may survive to this day. When John Freely came across this remarkable story in an old Jewish bookshop in Istanbul, he was instantly fascinated. Brilliantly evoking the world of 17th-century Jewish diaspora in the Ottoman empire, the ghettoes of Venice and Rome, the bazaars of Cairo, the Sultan's palaces in Istanbul and the synagogues of North Africa, Freely takes us deep into the esoteric world of Jewish mysticism and a messianic cult which still inspires belief in the Kabbalah.