First Order Categorical Logic : Model-Theoretical Methods in the Theory of Topoi and Related Categories

Grothendieck topoi.- Interpretation of the logic in categories.- Axioms and rules of inference valid in categories.- Boolean and heyting valued models.- Completeness.- Existence theorems on geometric morphisms of topoi.- Conceptual completeness.- Theories as categories.- Classifying topoi.- Corrections to "first order categorical logic".