The paper introduces a novel user interface called the see-through interface, which includes semi-transparent interactive tools known as Toolglass widgets and viewing filters called Magic Lens filters. These tools are designed to provide a rich and concise vocabulary for operating on application objects, allowing users to position widgets with one hand while controlling a cursor with the other. The widgets can be customized to modify the presentation of application objects, revealing hidden information, enhancing data, or suppressing distracting details. The see-through interface offers several advantages over traditional controls, including reduced steps, cursor motion, and errors, and can be used across multiple applications. The paper discusses the implementation of the see-through interface in the Multi-Device Multi-User Multi-Editor (MMM) framework, using the Gargoyle graphics editor as a testbed. It also explores various examples of widgets and lenses, such as shape and property palettes, clipboards, previewing lenses, selection tools, grids, and visualization tools. The authors highlight the benefits of the see-through interface, including its ability to provide unlimited space for tools, support for small and large displays, and the potential for personalized widget collections. The paper concludes by discussing future work, including the development of new widgets, algorithms, and compositions of widgets and lenses.The paper introduces a novel user interface called the see-through interface, which includes semi-transparent interactive tools known as Toolglass widgets and viewing filters called Magic Lens filters. These tools are designed to provide a rich and concise vocabulary for operating on application objects, allowing users to position widgets with one hand while controlling a cursor with the other. The widgets can be customized to modify the presentation of application objects, revealing hidden information, enhancing data, or suppressing distracting details. The see-through interface offers several advantages over traditional controls, including reduced steps, cursor motion, and errors, and can be used across multiple applications. The paper discusses the implementation of the see-through interface in the Multi-Device Multi-User Multi-Editor (MMM) framework, using the Gargoyle graphics editor as a testbed. It also explores various examples of widgets and lenses, such as shape and property palettes, clipboards, previewing lenses, selection tools, grids, and visualization tools. The authors highlight the benefits of the see-through interface, including its ability to provide unlimited space for tools, support for small and large displays, and the potential for personalized widget collections. The paper concludes by discussing future work, including the development of new widgets, algorithms, and compositions of widgets and lenses.