Donald J. Robertson is the author of seven books including "How to Think Like a Roman Emperor"; the graphic novel "Verissimus", about the life and philosophy of Marcus Aurelius; a philosophical biography, "Marcus Aurelius: The Stoic Emperor"; and "How to Think Like Socrates", a guide to applying Socratic wisdom to modern life, based on the story of his life.

Donald is a cognitive-behavioural psychotherapist, writer, and trainer, specializing in the relationship between ancient philosophy and modern self-improvement psychology. Donald is known for his work on Stoicism and evidence-based psychotherapy. He was born in Ayr, Scotland, but now lives in Quebec and Greece.