John Joseph Cassidy (born 1963) is an American journalist and British expatriate who is a staff writer at The New Yorker. He is a contributor to The New York Review of Books, and previously, an editor at The Sunday Times of London and a deputy editor at the New York Post. He received his undergraduate degree from University College, Oxford, studied at Harvard University on a Harkness Fellowship, and received a master's degree in journalism from Columbia University and a master's in economics from New York University.
He is the author of the well-received Dot.con: The Greatest Story Ever Sold, which examines the dot-com bubble, and How Markets Fail: The Logic of Economic Calamities, which combines a skeptical history of economics with an analysis of the housing bubble and credit bust. He is also well known for his biographical and economic writing on the famous Cambridge economist John Maynard Keynes, whom he interprets in a largely positive light