Book excerpt: This book constitutes the refereed proceedings of the 18th International Conference on the Application and Theory of Petri Nets, ICATPN'97, held in Toulouse, France, in June 1997. The 22 revised full papers presented in the volume were selected from a total of 61 submissions; also included are three invited contributions. All relevant topics in the area are addressed. Besides a variety of Petri net classes, workflow management, telecommunication networking, constraint satisfaction, program semantics, concurrency, and temporal logic are among the topics addressed.