Skims the surface of rebound headaches which can be triggered by caffeine. Adds incentive to cutting caffeine from your diet, however, doesn't offer much information specific to caffeine headaches.

Excellent link on Rebound. Caffeine can be a cure (it can stop a migraine or spinal headache cold), or a cause of Migraine, so those thinking of a morning cup of coffee as a vitamin... beware! :)