Library to build graphical user interfaces (GUIs) originally for X Window. Designed to be small, efficient, flexible. Coded in C, in very object-oriented style. Language bindings: C++, Perl, Python, Objective-C, Guile. [Open Source, LGPL]

A source code editor widget for GTK+. It is currently used, in one version or another, in several GTK+/GNOME applications, including gIDE, VDKBuilder, GXEdit, and Bluefish. [Open source, LGPL]

GTK-based CD player and ripper for Linux; with an internal encoder.

Free multithreaded ftp client for *NIX based machines running X11R6 or later.

This library implements a full callback system for use in widget libraries, abstract interfaces, and general programming. It is a complete library with the ability to connect an abstract callback to a class method, function, or function object.

GTK+ reference documentation.

Uses Tor's libraries to create installation packages of GTK.

A useful set of widgets for creating GUI's for the Xwindows system using GTK+.

"Windows impersonator" is a GTK theme that blends well into the Windows desktop environment.

A GTK+ and GNOME book online which is also available for purchase.