Ph.D thesís submitted to Princeton University. Discusses sources of Islamic law. Traces the history of land Management, taxes and public finance during Sassanid Iran and Byzantine Rome and the ways Arabs were influenced by these ancient practices. No clear distinction between ghaníma and fai' existed during the life-time of the Prophet. The decision of non-distribution of conquered lands and imposition of kharäj was personal ijtihãd of Caliph “Uman The rate of kharäj, jizya and 'ushr were higher in early Islam than under the Sassanid and Byzantine rulers. Most of the early Muslim practice in the conquered lands followed foreign administrative precedents. Caliph “Umar II levied 'kharäj on kharäjı 'lands irrespective of the religion of the owner. Thus a Muslim-who bought kharäjí land had to pay both kharäj and 'ushr In practice this did not work out. The later Umayyads reverted to financial malpractices; greed for land and multiple taxation. The Abbãsids tried to follow the example of 'Umar II but could not do so on political grounds. There is a lot of confusion about the exact meaning of ghanîma and ƒai'. Differentiation between movable and immovable spoils of war seemed more reasonable and practicable and was accepted in different degrees by most jurists except al-Shafiî and Ibn Hazm. The author discusses in detail the classification of land and the juridical differences relating to it. Kharäj and jizya were not differentiated for a long time. The Umayyad practice differentiated them. Jurists incorporated this practice into law. The jurists hated the imposition of taxes except jizya, o kharäj and 'ushr from non-Muslim traders. The i jurists considered any newly imposed tax as illegal. The object of kharäj was fai' land itself, although kharäj was assessed on the crop. The Hanafî jurists also distinguished land on the basis of source of water. A land irrigated by water from a river in the conquered area would pay kharãj. If the land was irrigated by a water source dug by Muslims it would pay only 'ushr. In the Sawad the Muslims followed the method of taxation by misaha as was Clone by the Sassanids. In Egypt they followed the Byzantine practice, levying a lump sum tax for a province or country which was distributed among its inhabitants. The “Abbãsids changed over to muqãsama. Despite juristic opposition, Muslim caliphs imposed additional levies on the people. But a few provinces also enjoyed reductions. The jurists prescribed rules for a just and fair collection of taxes. Tax-collectors were advised to treat the assessees kindly. Two calendars (solar and lunar) were used side by side in the Muslim Eands. Muslims also applied the system of tax-farming for collection of taxez. Expenditure of zakäh and 'ushr followed the Qur'ãnic injunctions. Other taxes were spent on the general public good. A part of the revenue was used to finance provincial needs, while a part was sent to the central treasury. The caliph appointed tax-collectors, who had certain qualifications concerníng knowledge, conduct and administration. A comprehensive treatment of the subject based on early historical sources. For jurists, historians and Muslim economists. Documented.