This monograph presents a new, systematic treatment of the relation between classifying topoi and classifying spaces of topological categories. Using a new gene

We give a general method of forcing over categories as a category-theoretic universal construction which subsumes, on one hand, all known instances of forcing i

Sheaves arose in geometry as coefficients for cohomology and as descriptions of the functions appropriate to various kinds of manifolds. Sheaves also appear in

Topos Theory is a subject that stands at the junction of geometry, mathematical logic and theoretical computer science, and it derives much of its power from th