  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.
