These multiple volumes (LNCS volumes 5592 and 5593) consist of the pe- reviewed papers from the 2009 International Conference on Computational S- ence and Its Applications (ICCSA 2009) held in Seoul (South Korea) from June 29 to July 2, 2009. ICCSA 2009 was a successful event in the International Conferences on Computational Science and Its Applications (ICCSA) series, previously held in Perugia, Italy (2008), Kuala Lumpur, Malaysia (2007), Glasgow, UK (2006), Singapore (2005), Assisi, Italy (2004), Montreal, Canada (2003), and (as ICCS) Amsterdam, The Netherlands (2002) and San Francisco, USA (2001). Computational science is a main pillar of most of the present research and industrial and commercial activities, and it plays a unique role in exploiting ICT innovative technologies. The ICCSA conference series have been providing a venue to researchers and industry practitioners to discuss new ideas, to share complexproblemsandtheirsolutions, andtoshapenewtrendsincomputational science. For the?rst time this year, ICCSA organized a number of special issues in international journals to publish selected extended best papers from ICCSA 2009, includingJournalofSupercomputing(Springer);ConcurrencyandCom- tation:PracticeandExperience(Wiley);Transactions onComputational Science (Springer); Mobile Information Systems (IOS Press); Journal of Algorithms in Cognition, Informatics and Logic (Elsevier); International Journal of Virtual Reality;and Journal of Universal Computer Science (JUCS).