- As information environments grow in complexity, we yearn for simple interfaces that streamline human cognition and effort. Users need to perform complex operations on thousands of objects. Human attention and available screen real estate are constrained. We develop a new fluid interface component for the visualization and adjustment of values while authoring, the In-Context Slider, which reduces physical effort and demand on attention by using fluid mouse gestures and in-context interaction. We hypothesize that such an interface will make adjusting values easier for the user. We evaluated the In-Context Slider as an affordance for adjusting values of interest in text and images, compared with a more typical interface. Participants performed faster with the In-Context Slider. They found the new interface easier to use and more natural for expressing interest. We then integrated the In-Context Slider in the information composition platform, comb in Formation. Participants experienced the In-Context Slider as easier to use while developing collections to answer open-ended information discovery questions. This research is relevant for many applications in which users provide ratings, such as recommender systems, as well as for others in which users' adjustment of values on concurrently displayed objects is integrated with extensive interactive functionality. Copyright 2008 ACM.