common-lisp LTK is a Common Lisp binding for the Tk graphics toolkit. It does not require any Tk knowledge for its usage. As it is written in pure Lisp, it is highly portable. The main objective for Ltk was to create a GUI library which is portable across different operating systems and Common Lisp implementations. Furthermore it should be easy to set up. So with the exception of one single function, the whole code of ltk is pure ANSI Common Lisp. No external programs besides a standard installation of tcl/tk are required. Ltk supports the following Lisp systems: Allegro, CMUCL, CLisp, ECL, LispWorks, OpenMCL, SBCL. Ltk was successfully tested using Lispworks, CLisp, CMUCL, SBCL under Linux and Lispworks, CLisp, and SBCL using Mac Os X, CLisp, Allegro and Lispworks using Windows.