The theory and methodology of design of general-purpose machines that may be controlled by a computer to perform all the tasks of a set of special-purpose machines is the focus of modern machine design research. These seventeen contributions chronicle recent activity in the analysis and design of robot manipulators that are the prototype of these general-purpose machines. They focus particularly on kinematics, the geometry of rigid-body motion, which is an integral part of machine design theory. The challenges to kinematics researchers presented by general-purpose machines such as the manipulator are leading to new perspectives in the design and control of simpler machines with two, three, and more degrees of freedom. Researchers are rethinking the uses of gear trains, planar mechanisms, adjustable mechanisms, and computer controlled actuators in the design of modern machines. J. M. McCarthy is Assistant Professor, Department of Mechanical Engineering, with a secondary appointment in the Computer and Information Sciences Department, University of Pennsylvania. Kinematics of Robot Manipulators appeared as a special issue of the International Journal of Robotics Research. Contributors: Atul Bajpai, V. Parenti Castelli, Raymond J. Cipra, Arthur G. Erdman, E. F. Fichter, Ferdinand Freudenstein, K. C. Gupta, C. Innocenti, A. Kumar, Z. C. Lai, David J. LeBlanc, Chih-Chung Daniel Lin, F. L. Litvin, J. M. McCarthy, G. Naganathan, Theodore W. Nye, Mayank S. Patel, B. Paul, Richard P. Paul, G. R. Pennock, Donald R. Riley, J. Rosa, Bernard Roth, George N. Sandor, A. H. Soni, M. M. Stanisic, Thomas Thompson, M. J. Tsai, R. Vijaykumar, K. J. Waldron, Tzu-Chen Weng, Yongxian Xu, D. C. H. Yang, Zhang Yi, Hong Zhang.