Kingsley Amis

This British author was the first to take on the colossal challenge—more in terms of public criticism than as a writing job—of keeping James Bond's world alive in ink. The first book in this series that was not penned by Fleming was Colonel Sun and it was written by this man under the pseudonym of Robert Markham. 

Well, if we'd been stuck with the leviathan task of carrying on Fleming's legacy we'd have hidden behind a pseudonym too.