Tables are part of our everyday lives. We use their surfaces at home, at work, to play, to eat, and for collaboration. Since a few decades, researchers envision and design interactive tabletops with computers and displays integrated into the furniture. This is a prominent way of making computers invisible and to instantiate the user interface as a physical interface: an interactive horizontal surface. Tabletop research, technologies, prototypes, and products are tightly coupled and in this article we synthesize historical information and map our findings onto a so-called hype cycle, usually representing the maturity and the visibility of specific technologies. We characterize the evolution in this domain, pointing out and tracing innovations as they stimulated and triggered key transitions in research and technology. This enables us to extrapolate the future of interactive tabletops.