As a retired primary school teacher, I will not be alone in owing David McKee a huge debt for inspiring many philosophy lessons and school assemblies.
While acting out Two Monsters was always a graphic way of illustrating the dangers of retaliation and mutually assured destruction (a pertinent lesson at the moment), and the Elmer books never failed to delight (while providing stimulation for many cross-curricular activities), my personal favourite was Tusk Tusk.
This book is, in many ways, the perfect illustration of the dangers of prejudice, discrimination and violence - yet one that manages to convey a hopeful outcome.