&SCons; is a software construction tool (build tool, or make tool) implemented in Python, which uses Python scripts as "configuration files" for software builds. Based on the design which won the Software Carpentry build tool competition, &SCons; solves a number of problems associated with other build tools, especially including the classic and ubiquitous &Make; itself.

Distinctive features of &SCons; include: a modular design that lends itself to being embedded in other applications; a global view of all dependencies in the source tree; an improved model for parallel (`-j`) builds; automatic scanning of files for dependencies; use of MD5 signatures for deciding whether a file is up-to-date; use of traditional file timestamps instead of MD5 signatures available as an option; use of Python functions or objects to build target files; easy user extensibility.

This paper discusses the goals of the &SCons; project, gives an overview of the design of &SCons; itself, describes the development process used, and discusses future plans and directions for the tool.