These Transactions publish archival papers in the broad area of Petri nets and other models of concurrency, ranging from theoretical work to tool support and industrial applications. ToPNoC issues are published as LNCS volumes, and hence are widely distributed and indexed. This Journal has its own Editorial Board which selects papers based on a rigorous two-stage refereeing process. ToPNoC contains: - Revised versions of a selection of the best papers from workshops and tutorials at the annual Petri net conferences - Special sections/issues within particular subareas (similar to those published in the Advances in Petri Nets series) - Other papers invited for publication in ToPNoC - Papers submitted directly to ToPNoC by their authors.

The sixth volume of ToPNoCincludes revised versions of selected papers from workshops and tutorials held at the 32nd International Conference on Application and Theory of Petri Nets and Concurrency. It alsocontainsa special section on Networks, Protocols, and Services, as well asa contributed paper submitted through the regular submission track of ToPNoC. The 14 papers cover a diverse range of topics including model checking and system verification, synthesis, foundational work on specific classes of Petri nets, and innovative applications of Petri nets and other models of concurrency. Thus this volume gives a good view of ongoing concurrent systems and Petri nets research."

This volume consists of the proceedings of the 30th International Conference on Applications and Theory of Petri Nets and Other Models of Concurrency (PETRI NETS 2009). The Petri Net conferences serve as annual meeting places to discuss the progress in the ?eld of Petri nets and related models of conc- rency. They provide a forum for researchers to present and discuss both app- cations and theoretical developments in this area. Novel tools and substantial enhancements to existing tools can also be presented. The satellite program of the conference comprised four workshops and seven tutorials. This year, the conference was co-located with the 20th IEEE/IFIP International Symposium on Rapid System Prototyping (RSP 2009). The two conferences shared ?ve - vited speakers. Detailed information about PETRI NETS 2009 can be found at http: //petrinets2009. lip6. fr/. The PETRI NETS 2009 conference was organized by Universit e Pierre & 1 Marie Curie as a part of MeFoSyLoMa, gathering research teams from numer- ous universities in Ile-de-France: CNAM, ENS de Cachan, Universit e Evry-V- d'Essone, Universit e Paris-Dauphine, Universit e Paris 12, Universit e Paris 13, and Telecom Paris-Tech. It took place in Paris, France, during June 22-26,2009. We would like to express our deep thanks to the Organizing Committee, chaired by Fabrice Kordon, for the time and e?ort invested in the conference and for all the help with local organization."