I think you mean The Noir Style by Silver and Ursini, since Silver and Ward never published a book called The Film Noir Style, as far as I know.
What was significant in the Silver/Ursini book is that they included films with gaslights, i.e., films set in the Victorian/Edwardian past. Without admitting it, this was a repudiation of the prior Silver/Ward contention that film noir is set in contemporary times (only).
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