Grey Eminence

Grey Eminence: A Study in Religion and Politics is a book by Aldous Huxley published in 1941. It is a biography of François Leclerc du Tremblay, the French monk who served as advisor to Cardinal de Richelieu. He was also known as Father Joseph and as l'éminence grise; that phrase originally referred to du Tremblay.

The political and economic commentator David P. Goldman called this book "The best book on the intelligence operations of the French state [during the 30 Years War]".