Interactive surfaces like tabletop computers provide large touch-enabled displays, support novel forms of interaction and collaboration, and extend computation to new environments. However, being a novel platform, the existing application pool is limited and applications existing for other platforms have to be re-developed. At the same time, smartphones are pervasive computers that users carry around and with a large pool of applications. This paper presents TIDE, a lightweight device composition middleware to bring existing smartphone applications onto the tabletop. Through TIDE, applications running on the smartphone are displayed on the tabletop computer, and users can interact with them through the tabletop’s interactive surface. TIDE contributes to the areas of device composition and tabletops by providing an OS-level middleware that is transparent to the smartphone applications, maintaining privacy by limiting content transfer between devices, and enhancing the usefulness of tabletops with already existing smartphone applications and software developers. We present the design and implementation of TIDE, the study of different interaction techniques to manipulate TIDE’s interactive content, and an analysis of different research directions. Initial user feedback shows that TIDE is easy to use, learnable, and convenient for collaborative activities and private environments.