I find researchers and writers who published very little, yet were influential in their respective fields of study, interesting. A good example of such a researcher was the mathematician C. F. Gauss, whose motto was "Pauca sed matura" ("Few but ripe"). Authors who seemed to have adhered to a similar motto were Harper Lee, J. D. Salinger, and G. T. di Lampedusa.
What are some good examples of scientists and other academics who were not prolific, yet were nonetheless able to leave their mark?
Let's set the bar the for maximum number of publications at 20, so as to include more possible scientists as answers to this question