If there's one thing every self-respecting blockbuster novel needs on its cover, it's a silhouetted man with his back to the reader, walking away, alone.

It's a style that tells you, with all the subtlety of a sledgehammer, that the book's protagonist is likely to be a maverick who doesn't play by the rules and does things his own way.

Real-world examples include James Patterson (The Family Lawyer), Lee Child (just about any of his Jack Reacher series) and Linwood Barclay (Parting Shot).