Martin Fowler
Pioneer of various topics around object-oriented technology and agile methodsA few, if any have had such great influence on the IT industry as Martin Fowler. No introduction needed, really!
But here is how Martin Fowler presents himself:
I'm an author, speaker, consultant and general loud-mouth on software development. I concentrate on designing enterprise software - looking at what makes a good design and what practices are needed to come up with good design. I've been a pioneer of various topics around object-oriented technology and agile methods, and written several books including "Refactoring", "UML Distilled", "Patterns of Enterprise Application Architecture", and "NoSQL Distilled". For the last decade I've worked at ThoughtWorks, a really rather good system delivery and consulting firm.
These days I spend my time helping colleagues share what they learned on martinfowler.com