Patterns developed by Martin Fowler, a specialist in object-oriented software, building business objects, the UML, patterns, author of "Analysis Patterns" and "UML Distilled" books. Also features a collection of links to related subject areas.
Object-oriented programming expert and consultant, one of the leaders in refactoring, author of the book 'Refactoring: Improving the Design of Existing Code', Extreme Programming proponent. Many useful articles and links.