  We identify and highlight certain landmark results in Samson Abramsky's work
which we believe are fundamental to current developments and future trends. In
particular, we focus on the use of (i) topological duality methods to solve
problems in logic and computer science; (ii) category theory and, more
particularly, free (and co-free) constructions; (iii) these tools to unify the
`power' and `structure' strands in computer science.
