In this issue

This is a special issue based on extended papers that were selected from those originally presented at the 4th International Workshop on Software Quality and Maintainability, which took place in March 2010 in Madrid, Spain. The guest editors of this special issue, Yiannis Kanellopoulos and Rudolf Ferenc, provide an interesting and informative introduction to these selected papers. I would like to thank the guest editors for all their hard work in managing the selection and reviews of these papers. I hope you find these papers of interest. Please let me know whether you have any suggestions or comments on this issue.