In my last column (“A ‘know-it-all’ approach to writing,” June 27), I wrote about Colm Toibin’s advice that a writer should know the whole story before writing his or her novel. Since I’ve always discovered the story by writing it, this for me would be a new way of working — but one I’m willing to try, if only I had my next big idea. I’ve usually started with a character of interest or, lately, with a challenge, such as “write a historical novel” or …