The author presents a revised and extended version of the top unsolved problems of information visualization that he outlined in an IEEE Visualization 2004 panel. These problems are not necessarily imposed by technical barriers; rather, they are problems that might hinder the growth of information visualization as a field. The first three problems highlight issues from a user-centered perspective. The fifth, sixth, and seventh problems are technical challenges in nature. The last three are the ones that need tackling at the disciplinary level.