I wrote Fearful Symmetry during the Second World War, and hideous as the time was, it provided some parallels with Blake's time which were useful for understanding Blake's attitude to the world. Today, now that reactionary and radical forces alike are once more in the grip of the nihilistic psychosis that Blake described so powerful in Jerusalem, one of the most hopeful signs is the immensely increased sense of the urgency and immediacy of what Blake had to say.
Preface of the 1969 edition of Fearful Symmetry : A Study of William Blake (1947)