If your research involves the work of Frank Norris, you’ve doubtless worked with Joseph R. McElrath and Douglas K. Burgess’s indispensable The Apprenticeship Writings of Frank Norris. It’s a superb volume, and it’s available free at Google Books.

The only thing lacking was an alphabetical list of essays. I made one several years ago and have posted it in .pdf form (typos and all) to the Frank Norris page at the Howells Society site and the American Authors site.