The book was comprehensive enough that it included any number of films that are tradionally considered noir. I wondered at the time what an encylopedia of noir would look like since he'd included so many noir films in the gangster encyclopedia. He didn't like to repeat himself, so you don't find the same film included in both the horror and science fiction books, even though some films could be considered either one or both.
Mr. Hardy died in 2014, evidently never having compiled the encyclopedia of noir. So we'll never know how he could have built a credible noir encyclopedia without including many of the films from the gangster film book, like THE KILLERS, OUT OF THE PAST, CRY OF THE CITY, RAW DEAL, CRISS CROSS, GUN CRAZY, THE ASPHALT JUNGLE, etc.