Aim of the monograph is to analyze the structure of the solution set of a differential equations in the more general case of abstract topological (infinite dimensional) spaces. Specifically, we consider both the spaces with a paucity of useful properties, e.g. locally convex spaces, and the more richly endowed spaces, e.g. Banach or Hilbert spaces. The related results are presented both for the single-valued case and multi-valued (differential inclusions) case.