Proceedings 17th International Workshop on Refinement
  We are proud to present the papers from the 17th Refinement Workshop, co-located with FM 2015 held in Oslo, Norway on June 22nd, 2015.   Refinement is one of the cornerstones of a formal approach to software engineering: the process of developing a more detailed design or implementation from an abstract specification through a sequence of mathematically-based steps that maintain correctness with respect to the original specification.   This 17th workshop continued a 20+ year tradition under the auspices of the British Computer Society (BCS) FACS special interest group.   This is the third volume that has appeared as an EPTCS proceedings, and we would like to thank the editorial board (and in particular Rob van Glabbeek) for their help and cooperation in making this happen.   The organisers would like to thank everyone: the authors, BCS-FACS, EPTCS, and the organisers of FM 2015 for their help in organising this workshop, the participants of the workshop, and the reviewers involved in selecting the papers. 
John Derrick, Eerke Boiten, Steve Reeves
cs.LO