Which author wrote the following in the unique forward to their Selected Stories edition in the Modern Library?  "The only thing that worries me a little is this Modern Library business.  Does publication in the Modern Library impose a moral obligation on an author, a sort of gentlemen's agreement that he will not write any more about the characters appearing in the volume?"

Answer:

P. G. Wodehouse in his Forward to Selected Stories by P. G. Wodehouse (126.5).