This chapter explores glanceability as a crucial requirement for several types of mobile visualizations, thereby integrating knowledge from the Vision Sciences, Visualization, Human-Computer Interaction, and Ubiquitous Computing. In mobile contexts, quick information needs are frequently occurring and differ from those in traditional visualizations that are designed for analyzing complex datasets. The chapter therefore discusses specific characteristics of glanceable mobile visualizations, explores different evaluation methodologies, and concludes with open challenges in the design of future glanceable visualizations.