This book is about the principles of Islamic banking. It explains the prohibition of Riba, and how the prohibition of usury was common to all monotheist religions. The use of Islamic laws in banking can bring together investors and managers; and also to explain mudarabah which is an arrangement where an investor entrusts his capital or merchandise to an agent. The book explains the belief of economic progress; that development does not imply Westernization. The encouragement of private sector activity is not, however, accompanied by any deliberate policy of fostering competition. The authority in an Islamic state is an interest that extends not only to criminal law, but also to the commercial law which affects both local and foreign companies. Although the law is usually applied consistently within individual countries, there is less consistency among Islamic states. The Koran and the sunnah, of course, provide the basis of the law in all Islamic states, but interpretation varies considerably. It finally explains the greatest challenge to the world of Islamic commerce in the 20thcentury is, to transform the classical mudarabah into an equally smooth functioning and efficient modern Islamic bank with the potential of almost unlimited growth.