GNU's Ubiquitous Intelligent Language for Extension, a library implementation of the Scheme language plus various convenient facilities. Designed to be linked into programs to make them extensible.

Growing article, with links to many related topics. [Wikipedia]

Guile bindings for Gtk+.

Object-oriented extension to Guile; very close in spirit to Common Lisp Object System, CLOS (CLtL2), but adapted for Scheme language; gives full OO system with multiple inheritance, generic functions with multi-method dispatch.

Maillist for general discussions about the guile-gtk project.