New user interface challenges are arising because people need to explore and perform many diverse tasks involving large quantities of abstract information. Visualizing information is one approach to these challenges. But visualization must involve much more than just enabling people to "see" information. People must also manipulate it to focus on what is relevant and reorganize it to create new information. They must also communicate and share information in collaborative settings and act directly to perform their tasks based on this information. These goals suggest the need for information visualization workspaces with new interaction approaches. We present several systems—Visage, SAGE, and selective dynamic manipulation (SDM)—that comprise such a workspace and a suite of user interface techniques for creating and manipulating integrative visualizations. Our work in this area revealed the need for interfaces that enable people to communicate with systems in multiple complementary ways. We discuss four dimensions for analyzing user interfaces that reveal the combination of design approaches needed for visualizations to support information analysis tasks effectively. We discuss the results of our attempts to provide multiple forms of expression using direct manipulation and propose areas where multimodal techniques are likely to be more effective.