What did Hannah Arendt really mean by the banality of evil?

Can one do evil without being evil? When Adolf Eichmann was being tried for his war crimes in the Nazi operation, Hannah Arendt, declared she found him as ‘neither perverted nor sadistic’, but as ‘terrifyingly normal’... Thomas White, writing in Aeon Magazine, re-examines how this controversial statement raised some important questions about the nature of evil.