Object-oriented programming: some history, and challenges for the next fifty years

This article is based on a lecture given on 22ndAugust 2011, on theoccasion of the scientific opening of the Ole-Johan Dahl hus at the Universityof Oslo. It looks at the foundational ideas fromSimulathat stand behindobject-orientation, how those ideas have evolved to become the dominantprogramming paradigm, and what they have to offer as we approach thechallenges of the next fifty years of informatics.