Book of Certainty: Sufi Doctrine of Faith, Vision and GnosisMartin Lings This work came into being because the author was asked by a friend to set down in writing what he considered to be the most important things that a human being can know. He was also asked to make it very easy, and despite the depth of all that it contains, it has in fact a remarkable simplicity and clarity, due no doubt to the constant use of traditional imagery which awakens and penetrates the imagination.A wonderful, short and sweet