In 1998, a chapter on realizability by his hand came out in the Handbook of Proof Theory. Characteristically, Anne’s text had been finished a few years before, faithfully meeting his deadline, but delays by other authors kept him updating, somewhat grumblingly, with all new results in the area. What he published had to be the complete state of the art.
Johan van Benthem and Dick de Jongh: Anne Troelstra (1939-2019)