Creator of Supermemo and the related algorithms (such as SM-2).
Also a proponent of Incremental Reading.
A very long history of Spaced Repetition according to Piotr Wozniak
https://www.supermemo.com/en/articles/history
Open source algorithm for spaced repetition developed by Piotr Wozniak from the late 1980s. Used in Anki.