This book consists of a collection of carefully selected review papers and lecture notes written by the author on Perturbative Quantum Chromodynamics (PQCD) and its experimental tests. A leading authority who has contributed significantly to the development of PQCD for more than 20 years, the author has selected articles on the basis of their present interest. These articles cover different aspects of the subject without unnecessary duplication and are accompanied by commentaries. Also, original material, specially written for this book, has been added to integrate and update the results and their presentation. Hence, more than providing a historical perspective on the subject, this volume also serves well as an authoritative guidebook on Perturbative QCD.