This paper, delivered at the Colloquium on Symbolism in Paris in June 1964, appeared in the Cahiers internationaux de symbolisme 6, Brussels 1964, pp. 3—26. The complete text of this account has been published in Henry Corbin, En Islam iranien: aspects spirituels et philosophiques, tome IV, livre 7, Paris: Gallimard, 1971. Other writings of Prof. Corbin have been published regularly in French in the Eranos Jahrbucher. His major works in English translation are: Avicenna and the Visionary Recital (Bollingen Series LXVI) N. Y. and London, 1960 and Creative Imagination in the Sufism of Ibn'Arabi, Princeton and London, 1969.