This paper describes the ideas behind and the use of the FIELD programming environment. FIELD is an integrated environment that is based on Unix programming tools and that runs on top of the X11 windowing system. It provides a consistent and complete interface to its tools. In addition, FIELD provides a variety of tools for program and data visualization. The key concepts behind FIELD are an integration mechanism based on a simple, central message server, an annotation editor for integrating access to the source file with the other tools, and the use of a high‐level user interface toolset.