Science is always changing. always developing. because new facts are discovered. new theories expounded and new thoughts developed. Hence it is always becoming a new knowledge. It thus becomes a new way of looking upon the facts and conditions of life and nature. Hence science cannot remain the same for ever. In other words. science is an instrument for discovering new knowledge and developing new thoughts and new ways of thinking. The same is also true of Political Science. It too is changing; it too is growing and developing constantly, as new facts are discovered and new theories are expounded As I have explained in a chapter of this book, even in Pakistan Political Science has changed, though its progress is not so fast as in the developed countries of the West. Many old theories were challenged or discarded and new ones introduced by various schools of political scientists and thinkers, especially in the Western countries. They have influenced the teaching of Political Science in Pakistan also. Consequently, the syllabuses of various universities in our country have been revised and updated from time to time, especially after 1980. In view of the new syllabuses of the Pakistani universities, I have thoroughly revised my book. It was formerly entitled PRINCIPLES OF POLITICAL SCIENCE. But in view of the changes and additions introduced in it. I have brought it out under a new title: POLITICAL SCIENCE THEORY AND PRACTICE. Though much of the old edition is still retained in it. nevertheless all new theories and explanations of the phenomena of politics have been incorporated in the new edition. I hope that it will not only present a comprehensive survey of the modem developments in Political Science, but will also meet all the requirements of the teachers and students of the degree classes as prescribed in the syllabuses of the Pakistani Universities. (For their convenience, these syllabuses are also copied in the beginning of this book).