's Nachts, translated in German as Nachts, is a children's book written and illustrated by German author Wolf Erlbruch written for the Dutch Kinderboekenweek, an annual event promoting children's literature. It is a story about a boy, Fons, who, unable to sleep, drags his father on a walk through town and encounters the most fantastic animals and creatures. Some of the things Fons sees along the way were specifically geared toward the Dutch reader, Erlbruch explained.