Nope, there's some shorts,too. I've got an ancient hardcover called The Adventures of Sam Spade, published by Tower Books in 1945. There are 3 Sam Spade stories: "Too Many Have Lived", "They Can Only Hang You Once", and "A Man Called Spade".Sadly it is the only Sam Spade story that Dashiell Hammett wrote.
He wrote a lot more about the Continental Op, though.