What is "local theory of Banach spaces"?

Banach space theory splits into several subtheories. On the one hand, there are an isometric and an isomorphic part; on the other hand, we speak of gl obal and local aspects. While the concepts of isometry and isomorphy are cl ear, everybody seems to have its own interpretation of what "local theory" means. In this essay we analyze this situation and propose rigorous definit ions, which are based on new concepts of local representability of operator s.