Action Semantics is a novel approach to the formal description of programming languages. Its abstractness is at an intermediate level, between that of denotational and operational semantics.  Meer

This introduction to Stone–Priestley duality theory brings modern tools in the area together in textbook format for the first time and covers applications to logic and theoretical computer science.  Meer

This definitive treatment of results in category theory and theoretical computer science covers classical material from new viewpoints and develops a wealth of new topics.  Meer