Fiction/non fiction

I have 100+ books that are not listed as fiction or non-fiction. They do not have a Dewey or LC classification. How can I find this information in order to edit these books?
Thanks

Probably easiest from Charts and Graphs. If you go to Genres section there, there's a group 'not set' in the Fiction vs Nonfiction chart. Clicking on it open a page that lets you pull all those in your catalogue. FWIW, mine are normally biographies, memoirs, journals and such

Dewey graph doesn't include 'not set', so you'll need to sort by it the catalogue

Fiction and non-fiction are determined by the genres feature. You can change it by looking at the right hand side of any work page for the "genres" section and clicking the pencil icon