From a conversation between Robert Caro and John R. MacArthur, marking the fortieth anniversary of the publication of The Power Broker, Caro’s biography of Robert Moses, which won the Pulitzer Prize. Caro is also the author of the multivolume biography The Years of Lyndon Johnson. MacArthur is the publisher of Harper’s Magazine. A first edition of The Power Broker, annotated by Caro, will be included in PEN America’s First Editions/Second Thoughts auction on December 2.

robert caro: By the time I started the book, Robert Moses had been in power for almost half a century. Moses’s people…