We write three kinds of author bios in this household:

1. short story introductions for year's best collections (which have tight wordage constraints);
2. longer author notes for our larger historical anthologies. (A complete set of our author bios from The Ascent of Wonder is available online.) These give more detail on the author and are also usually used to carry on the overall argument of the book.
3. And the occasional longer biographical essay, which usually ends up in some form in The New York Review of Science Fiction.

Because of my recent experience with Wikipedian "editing," I am considering releasing the complete set of author bios from the anthologies of both David Hartwell and Kathryn Cramer to the Internet under Creative Commons in order to raise the level of author bio discourse. (There is a certain amount of hard labor involved in this, and I haven't figures out how to do it yet. Suggestions welcome.)

Since our story notes usually go with a particular story, I'm going to skip the discussion of how to position the story in the note, and instead focus on what information needs to be assembled about the author.

Here are the basic pieces of info we collect before writing a note:

• The author's correct name and any known pseudonyms
• year of and place of birth and death (if deceased)
• where the author lives and minor family details
• the URL of the author's website. Failing that, the URL of the best tribute site. If the author has a blog, the URL of the blog.
• A brief summary of the highlights of the authors career and life. This may or may not include a summary of awards.
• An interesting quote from the author, usually taken from online interviews but sometimes elicited in correspondence. Do collect listings of interviews,  the more the better.
• The author's three most recent books, with brief descriptions (I love Amazon as a source for this info!)
• The author's three most important books or stories
• Relationships to others in the field or other notable people (Greg Bear is married to Poul Anderson's daughter; Rudy Rucker is the great grand son of Georg Wilhelm Friedrich Hegel; etc.)
• The authors significance in terms of trends within the science fiction field (Bruce Sterling was the chief spokesman for the cyberpunk movement)
• Other interesting aspects of an author's life. Other areas of achievement.
• I suppose I should add "in the tradition of . . ." but that is such a tried cliche of flap copy that we usually leave it out.

Lists of authors' awards and complete bibliography are usually available elsewhere. Link to them. But if the usual sources are inaccurate, provide better info. And finally, cover good new writers and cover people no one knows much about.

The most important thing to understand about writing an author bio is that this is a form of literary characterization. Details that enhance the bio by making the author a more rounded character may be crucial even if not otherwise relevant.