Roy's books cover several fields: the history of geology, London, 18th-Century British ideas and society, medicine, madness, quackery, patients and practitioners, literature and art, on which subjects (and others) he published over 200 books are articles.
How does G. S. Rousseau get so much work? He's absolutely one of the worst jargon-free writers I've ever encountered in the world of academia -and that's saying a lot.