I've reviewed two of his Tor horror novels, Dead White (1983) and Cast a Cold Eye (1987), and recommend both to readers looking for quiet, unassuming and atmospheric scares. Panther (Signet 1979) and The Kill (Tor 1982) remain on my find-and-read list; then you'll see a sampling of covers for his holiday-themed Halloween Horrors from '86, and you can read a good review of that one here. You find any Ryan's titles on your used bookstores searches, grab 'em!
First Blood (1982) review
3 hours ago