How do you tell a good idea from a bad book idea?

One might say that a "good" book idea is rich and has many intriguing rooms for the writer to explore. It is sufficiently fecund that it enables the writer to explore the most pressing concerns (emotional, intellectual, moral, social and political) he or she has at the moment. More important than anything else, it must be an idea the writer is excited about---and can remain excited about for many years during the book's composition, an idea so prismatic, multi-sided and full of mystery that whenever he pokes at it he feels the frisson of discovery.

What do you do with a idea when it first hits you? How do you develop it?

Please bear in mind that ideas do not a story make. An idea by itself may be enough for an essay, but the engine for all fiction is character---a cast of interesting people doing things that makes a reader ask, "What happens next?" If one starts with an idea (instead of a character in a situation), he must incarnate that idea in a compelling "ground situation" (John Barth's phrase for a character's "conflict"), then proceed to complicate the conflict even more. All fiction is based on a simple truth: Your main character either wants something (in which case you frustrate his getting it) or there's something in his or world that is causing discomfort, distress or pain, which he must attempt to remove. From those beginnings all drama springs.

Do you use a journal?

Yes, I've kept a writer's journal since 1972 (and also written in diaries since I was about 12). The writer's journal is basically a memory-aid, something we keep for recording potentially useful ideas, scraps of interesting language we've heard. When stacked all together my primary set of writer's journals are twelve-inches deep, and I canvass all of them when I'm revising a major work of fiction.

Have you pursued ideas that you had to discard later, because they didn't work out?

My filing cabinets are full of unfinished short stories (and six early novels) I wrote only to discover that, no, I wasn't interested in continuing with them or seeing them published.

Do you discuss your ideas with other people/writers before, while, or after you write them?

No. I trust my own ideas well enough to execute them as stories before I show the finished product to anyone. I have no problem with entertaining suggestions for a work after I've worked my way through a good draft of a story or novel, but I feel that "too many cooks" can spoil a fictional concoction when it is in the early stages of unfolding.

Where do you get your ideas?

N/A