This paper describes a high-level, screen oriented programming environment that supports problem solving by tool selection and tool composition. Each tool is a powerful parameterized program that performs a single high-level operation (e.g., sort a file). To solve a given problem, the user first interacts with the system to compose a task overview consisting of a sequence of generic operations. Such sequences are called compositions. Once an overview is established, a second part of the environment interacts with the user to help expand the generic operations into a corresponding sequence of parameterized tool calls. When a composition is expanded to include details such as parameterization and punctuation it is called a script. This script, when executed by the underlying runtime system, computes a solution to the specified user task. The current environment runs under the Unix operating system on a VAX 11/785, and uses a Bitgraph terminal with a 640x720 bitmap display and standard keyboard as the principal interface device.