Let me, as Henry James used to say, be brief:
I have decided that the critical term "fix-up" needs to be obliterated. What was once a modest descriptive for a very specific type of novel has long since metastasized, swelling to many times its original meaning and in the process doing a great deal of harm to many works of fiction that did not deserve to be so mistreated.
If you're curious about my reasoning, what does and does not properly constitute a fix-up, and what conceivable harm an innocuous little compound noun can do, you can read about it in A Nettlesome Term That Has Long Outlived Its Welcome. To sweeten the pot, I've thrown in two brand-new and original flash fictions, both in collaboration with writers more famous than myself.
Oh, and forewarned is forearmed: The essay is nine thousand words long.