David Harel is the Dean of the Faculty of Mathematics and Computer Science at the Weizmann Institute of Science in Israel. He is also co-founder of I-Logix, Inc., Andover, MA, and of SenseIT Technologies, Ltd. (DigiScents Israel). His research interests are in theoretical computer science (especially computability, automata theory and logics of programs), and in software and systems engineering (especially specification and modeling, object-oriented analysis and design, and visual languages), as well as the aesthetic layout of diagrams, clustering algorithms and the synthesis and communication of smell. He is the inventor of the language of statecharts (1983), was part of the team that designed the Statemate (1984-1987) and Rhapsody (1997) tools, and was co-inventor of LSCs (1998). His work is central to the behavioral aspects of the UML. He devotes part of his time to expository work: In 1984 he delivered a lecture series on Israeli radio, and in 1998 he hosted a series on Israeli television; some of his writing is intended for a general audience (see, for example, Computers Ltd.: What They Really Can't Do , Oxford University Press, September 2000). He has received a number of awards, including ACM's Karlstrom Outstanding Educator Award in 1992, and the 1997 Israeli Prime Minister's Award for Software. His book, Algorithmics: The Spirit of Computing (Addison-Wesley, 1987, 2nd. edn. 1992) was the Spring 1988 Main Selection of the Macmillan Library of Science. He is a Fellow of the ACM and of the IEEE.

The play-in/play-out method and tool presented in this book is a powerful new approach to software and systems engineering and modeling based on formal methods and program semantics. The life sequence charts (LSC) as the language of this approach generalize the message sequence charts of UML and are presented in this book for the first time in a coherent and systematic way.

The method described is fascinating from the scientific point of view. The associated play-engine tool available from the authors' Web site has broad appeal to professionals in software engineering, systems engineering, and modeling and simulation.