LTK was written by Peter Herth.
Although the last release is somewhat dated, the project is still under active development. Most activity happens on its mailing list
Recent improvements could could be found in svn repo at http://ltk.rplay.net/svn/trunk/ltk
Note for usersThe documentation is incomplete it is recommended that users of this library takes a look at ltktest in the ltk.lisp file to see an example of how it works as well as the pdf or the online documentation on LTK website
Also there is an error in the tutorial where the (make-instance 'button) is (make-instance `button) i'm sure lisp experienced programmers will recognise the difference but it may trip up learning lisp programmers.
IssuesOne unfortunate problem is that LTK mysteriously fails to run on some Windows computers, depending on what programs happen to be running in the background. People are encouraged to either donate a Windows box for testing, or helpfully volunteer to track the issue down.
This may be an issue limited to certain Lisp implementations, as SBCL has not been observed to manifest this problem.