ministration of the property tax. In states where substantial advances have been made in revenue and tax system, the constitutional and statutory provisions have given recognition to certain major defects, such as: (a) the provision for the classification and differential taxation of property; (b) provision for effective central supervision and co6rdinated tax administration; (c) separation of sources of state and local revenues, and (d) the establishment of necessary revenue sources as a means of relieving property and in acknowledgment of the principle that taxation should be levied, in so far as possible, on benefits received and/or ability to pay. Studies of changes and advances made in property tax administration attest the substantial measure of success that has been achieved. They demonstrate the efficacy of just guiding principles and of sound organization and methods in assessment and tax collection administration, even where the revenue laws themselves are antiquated and in many respects defective and utterly inadequate.