Dead is better. That is the opinion of most working biographers when asked whether it is easier to write about a living subject or the long departed. In my 40-year career as a biographer, I have covered both the living and the dead—John J. McCloy, McGeorge Bundy, J. Robert Oppenheimer, Robert Ames—and twice I have started my research with a subject who was very much alive, but who, by the time I was finished, was dead (McCloy and Bundy).
The living invariably manufacture obstacles. Irrationally, they go by the assumption that it is their life, so they try in some way to keep the biographer on a leash. My first subject, McCloy—the powerful but secretive Wall Street lawyer—actually tried to persuade my editor to cancel the contract.