Asasiyyat al Tamwil al Islami (Fundamental of Islamic Finance) This book attempts to establish a theory of Islamic finance. it is deeply founded on the Fiqhi premises as a blend them with economics and the science of finance. It refuses the extreme unrealistic presumption that Islamic finance and Islamic banks must play a role tilted to businesses in their distribution of financial resources. It rather argues that the market demand and supply determines who receives the finance. this is a fundamental premise of an Islamic market system. However it argues that Islamic finance is developmental by its nature because it is always build around the real market of production and distribution. The book does not take a stand, which is common among Muslim writers, against Murabahah. It rather considers Murabahah as a main and most important contract/tool of financial intermediation. It also argues that Islamic financial intermediation is never understood clearly when think of it as merely an investment vehicle which uses Mudarabah and Musharakah tools to finance business. Islamic financial intermediation is rather built on Wakalah/agency relationship granted by surplus units to Islamic banks for the purpose of maximizing their profit/return through helping the deficit units in fulfilling their desires to acquires goods and services whether for consumption or for production purposes. It goes on to determine that Islamic financial intermediation is and should be more keen of determination of planned exits of its financing operations than conventional financial intermediaries and that can best be done by focusing on Murabahah and Ijarah. The book offers a new direction for Islamic finance while it relates it to its original sources in the Qur'an and the Sunnah. At the same time it stands very strongly against the ill practices of Tawarruq and other untrue practices that do not reflect the true Islamic theory of finance.