The first part of this book is designed to display the sources and principles of economics and trade transactions in the Islamic community. It analyzes the judicial injunctions against riba and proves that riba including interest is prohibited. Basing the argument on theoretical (Quran and Sunna) as well as the customary practice during the life of the messenger of God in Mekka and Al-Madina. Notably, the Islamic teachings covers both the worldly and religious affairs.This is a very revealing indication that "Islam" does not only regulate the relations of the human beings with God, but also extends to regulating (i) the relationship of the ruler with the ruled through "al-shura", and (ii) economic and financial transactions in the market. Notable among these transactions: a) the abolition of riba and instigating interest-free economy, (b) providing the basic needs of society, (c) achieving social justice by applying zakat levy and other ordinances, and last but not least inheritance law and redistribution of State land for public benefits.The second and third part of the book explains and proves that prohibition of riba does not circumvent trade or paralyze the economy. On the contrary by eliminating injustice inherent in riba, the banking system will be liberated from discrepancies and the economy will perform more efficiently by mitigating the evils of riba.