This special issue contains extended versions of four papers from the second IEEE International Conference on Software Testing Verification and Validation (ICST 2009). These four papers were selected based on the reviews from members of the program committee and subsequently subjected to additional rounds of review and revision. We issued 10 invitations to this special issue. Three authors declined to submit, two were not selected after submission, one chose not to revise the paper after being reviewed, and four papers were eventually accepted. The first paper is Reducing Logic Test Set Size While Preserving Fault Detection, by Kaminski and Ammann. This paper introduces a new logic criterion, Minimal-MUMCUT, which has less overlap in terms of faults detected than previous logic criteria, and thus requires fewer tests. It is also provably stronger than the widely used MCDC. The second paper is Improving Penetration Testing through Static and Dynamic Analysis, by Halfond, Choudhary, and Orso. Penetration testing seeks vulnerabilities in software by simulating attacks. Halfond et al. use new software analysis techniques to improve penetration testing. The conference version won the best paper award at ICST 2009. The third paper is An Approach for Testing Pointcut Descriptiors in AspectJ, by Romain Delamare, Baudry, Ghosh, Gupta, and Le Traon. Aspect-oriented programming uses ‘crosscutting concerns’ to increase modularity in software, by encapsulating pieces of software that appear in separate units into their own objects. Delamare et al. have invented testing techniques to find faults in the descriptions of the aspects. The fourth paper is JDAMA: Java Database Application Mutation Analyzer, by Zhou and Frankl. Modern software uses databases much more than in the past, opening up a place for software faults to appear. Database queries are often long, complicated logical expressions, with lots of potential for faults. When the faults are subtle, most queries will return the correct information, and when they do fail, the tables that are returned often look correct. Zhou and Frankl extend a previous mutation-based approach to use analysis and instrumentation of bytecode. All four papers in the ICST 2009 special issue are partially drawn from each of the first authors' PhD Dissertations. The ICST organizers take this as a strong measure of success of the conference. Six years ago, if a student asked ‘where is the best place to publish a paper on testing software?’ the answer was far from clear. The field had several special purpose testing conferences, and many conferences included testing as one topic, but not the main topic. We also had conferences that were intentionally kept very small, even as field was growing. The conference that published the most testing papers was the International Symposium on Software Reliability Engineering, even though its main topic was not testing. It was clear that we had a real need; a need for a large-scale, high quality, broad conference that included all facets of testing, verification, and validation. Thus, a small group (initially Anneliese Andrews, Lionel Briand, and Jeff Offutt) started developing ideas for a new conference in the summer of 2005. This group grew quickly to 30 or 40 people who shared this vision of a new major conference in software testing. A steering committee was elected from that group in 2007 (Andrews, Baudry, Briand, Harman, Hierons, Le Traon, Mathur, Offutt, Williams) and a preliminary charter was approved in 2007, followed by a proposal to the IEEE Computer Society in 2007. The first ICST conference was held in Lillehammer, Norway in 2008, the second in Denver, USA in 2009, the third in Paris, France in 2010, and the fourth in Berlin, Germany in 2011. Because of the obvious overlap, STVR committed to offering a special issue to ICST on a yearly basis. The special issue for ICST 2008 appeared earlier this year, and the special issues for ICST 2010 and 2011 should appear next year. On a final note, we express our gratitude to the many hard working people who helped organize ICST 2009 and this special issue. The steering committee members provided valuable advice and we were assisted by industry chairs Wolfgang Grieskamp, Christian Zapf, and Robert Binder, and general chair Anneliese Andrews. The success of ICST 2009 and the high quality papers in this special issue is due to the efforts of these individuals as well as the Technical Program Committee for ICST 2009 and the additional reviewers for this special issue. We also appreciate the hard work from the ICST 2009 local arrangements chair, Susanne Sherba, the web chair, Orest Pilskalns, and our publicity chairs, Robert Feldt, Jens Krink, Shaoying Liu, Jose Maldonado, and Tao Xie. And last but certainly not least, we thank all the authors who spent valuable time in preparing papers for ICST 2009 and this special issue. 7 July 2011