When Niklas Luhmann, the German sociologist, became professor, he was asked about his research project. His famous answer:

"My project: theory of society. Duration: 30 years. Costs: zero."

Twenty-nine and a half years later, he published the last chapter of what is probably the most systematic and comprehensive sociological theory ever written. In these 29 and a half years, he published roughly another 60 books and hundreds of articles on a huge variety of subjects. And all of it was achieved by writing one smart note at a time.