Jeff Ely, writing in Cheap Talk:
The absolute worst thing you can do with your title is to insert a colon into it. (quiet down beavis!) As in, Torture: A Model of Dynamic Commitment Problems. Or Kludged: Asymptotically Inefficient Evolution. In the first case you have just ruined a seminal-signaling one-word title by adding spurious specificity. In the second, you just took an intriguing one-world title and turned it into a yawner.
The second worst kind of title is the question mark title.