books.google.co.uk - Starting from the classical finite-dimensional Galois theory of fields, this book develops Galois theory in a much more general context. The authors first formalize the categorical context in which a general Galois theorem holds, and then give applications to Galois theory for commutative rings, central...http://books.google.co.uk/books/about/Galois_Theories.html?id=fNJTFzYSgMUC&utm_source=gb-gplus-shareGalois Theories
