Logic Based Program Synthesis and Transformation : 9th International Workshop LOPSTR’99 Venice Italy September 22 24 1999 Selected Papers This book constitutes the thoroughly refereed post proceedings of the 9th International Workshop on Logic Based Program Synthesis and Transformation LOPSTR99 held in Venice Italy in September 1999. The 14 revised full papers presented together with an invited paper and 2 tutorial lectures have gone through two rounds of reviewing and revisions. The book is divided into topical sections on software development analysis and specialization transformation and verification