Book excerpt: This volume contains papers selected from the contributions to the 4th International Workshop on Graph Grammars and Their Application to Computer Science. It is intended to provide a rich source of information on the stateof the art and newest trends to researchers active in the area and for scientists who would like to know more about graph grammars. The topics of the papers range from foundations through algorithmic and implemental aspects to various issues that arise in application areas like concurrent computing, functional and logic programming, software engineering, computer graphics, artificial intelligence and biology. The contributing authors are F.-J. Brandenburg, H. Bunke, T.C. Chen, M. Chytil, B. Courcelle, J. Engelfriet, H. G|ttler, A. Habel, D. Janssens, C. Lautemann, B. Mayoh, U. Montanari, M. Nagl, F. Parisi-Presicci, A. Paz, P. Prusinkiewics, M.R. Sleep, A. Rosenfeld, J. Winkowski and others.