This volume consists of invited papers written by eminent researchers working in the areas of theoretical computer science. The contents of the papers reflect the current trend of research being carried out in each of the areas. Some of the areas featured are petri-nets, distributed systems, map-generating systems, Lindenmayer systems, logic, cryptography, graph grammars, probabilistic automata, array grammars and pattern recognition. Many of these areas contain open problems and it is hoped that younger research workers will be motivated to work on them. In addition, some of the models designed, constructed and presented are suitable for practical applications such as in computer graphics, cryptography and distributed computing.