In this workshop, we will review and discuss opportunities, technical challenges and problems with cross-device interactions in interactive multi-surface and multidevice ecologies. We aim to bring together researchers and practitioners currently working on novel techniques for cross-surface interactions, focusing both on technical as well as interaction challenges for introducing these technologies into the wild, and highlighting opportunities for further research. The workshop will help to facilitate knowledge exchange on the inherent challenges of building robust and intuitive cross-surface interactions, identify application domains and enabling technologies for cross-surface interactions in the wild, and establish a research community to develop effective strategies for successful design of cross-device interactions.