Matthew Oates has spent 50 years trying to unravel the Purple Emperor's secrets. Many mysteries remain unsolved, but enough are revealed in this book to enable experts and non-experts alike to go out in search of a butterfly that thrills and enthrals all who encounter it. This is a good-news species, at a time of massive wildlife decline. And this is a joyous - often rapturous - account, written in plain English, as a labour of love.