This volume contains the proceedings of the 12th International SPIN Wo- shop on Model Checking of Software, held in San Francisco, USA, on August 22-24,2005.SPIN 2005is a forum for practitionersand researchersinterested in model-checking based techniques for the validation and analysis of communi- tion protocols and software systems. The workshop focuses on topics including theoretical and algorithmic foundations and tools for software model checking, modelderivationfromcodeandcodederivationfrommodels,techniquesforde- ing with large and in?nite state spaces, and applications. The workshop aims to foster interactions and exchanges of ideas with all related areas in software engineering. It has traditionally drawn contributions from both academia and industry. The SPIN workshop series started 10 years ago, in 1995. Since then, SPIN workshopshavebeenheldonanannualbasisatMontr' eal(1995),NewBrunswick (1996), Enschede (1997), Paris (1998), Trento (1999), Toulouse (1999), St- ford (2000), Toronto (2001), Grenoble (2002), Portland (2003) and Barcelona (2004). All but the ?rst SPIN workshop were organized as satellite events of larger conferences, in particular of CAV (1996), TACAS (1997), FORTE/PSTV (1998),FLOC(1999),theWorldCongressonFormalMethods(1999),FMOODS (2000), ICSE (2001, 2003) and ETAPS (2002, 2004). This year, SPIN was held as a satellite event of CONCUR 2005. The co-location of SPIN workshops with conferenceshas provento be verysuccessfulandhas helpedto disseminateSPIN model checking technology to wider audiences. Since 1999, the proceedings of the SPIN workshops have appeared in Springer's Lecture Notes in Computer Science series. ThehistoryofsuccessfulSPINworkshopsisevidenceforthematuringofso- waremodel-checkingtechnology.Whileinearlieryearsthefocus oftheworkshop series was algorithms and tool development around the SPIN model-checker, its scope was widened several years ago to include other software model-checking techniques, tools and applications.
