Who is Harold Oblowski from Bag of Bones and what is their importance?

Mke's agent, Harold is both loved and hated in publishing circles. He doesn't cope well with bad news and words like writer's block would have him hopping a flight from New York to Derry to hold Mike's hand until he overcame whatever ailment prevented him from continuing to pump out a best seller each year. He has an office on the thirty eighth floor on Park Avenue with a great view of the East Side. Harold believes he has a connection with his writers that transcends the physical. Harold believes in the Noonan formula of writing where an author religiously puts out one best seller each and every year. Not enough so that readers get sick of hearing from their favourite author, but enough so that they are not forgotten. When Mike tries to take a year off, Harold tells him that he simply isn't the kind of author who's readers would forgive a lapse of that kind.