These are just personal favorites. Let me know if you have some too!
Fantastic Fiction >> I have this site bookmarked on every computer and every browser I use. It’s basically a searchable database of books and authors, but it’s organized better than any other one I’ve seen, and especially well organized for mystery writers who have multiple series. Each author has a page with their series listed, each book in the series (in chronological order), each book has a link to a summary, and each author has a brief bio. Stand alone novels are listed, as are collections and awards and release dates for new books! Some author’s pages also have “this author recommends” at the bottom. This site is maintained by a small family run company in Lancashire, UK. It’s very impressive and not only for mystery novels and authors.
Stop, You’re Killing Me >> Devoted to mystery fiction, this site has always impressed. Created by one woman in 1998, the site is now maintained by two avid mystery fans. You’ll fine “read alike” lists, as well as novels organized by location (where mystery is set), as well as indexes for Jobs, Historic, Genre, and Diversity. Book awards, new releases, and reviews are also included.
PNC Book Exchange >> Local to Seattle? Make sure to check out the twice a year Book Exchange at Phinney Neighborhood Center. Their mystery book exchange is what gave me the idea for our book group. An entire room filled with mystery novels to exchange. You can purchase, or you can turn in your old mysteries, receive “tickets” and use those to get new (used) books. Fantastic way to feed your addiction to mystery novels and get a free taste of new authors.