Nick Ing-Simmons was the auther of 
Perl/Tk.  He 
died of a heart attack
 at the age of 48 on 2006-09-26.
RLH 2006-09-26: That is sad. Nick was always very helpful.
 Reference  edit
- Thanks Nick , Graham Barr, 2006-09 , Graham Barr, 2006-09
AMG: Not to take anything away from Nick, but the linked article and its comments attribute the development of 
Tk itself to Nick.  Sample quote: "Tk was initially born out of frustration that perl didn't have a native GUI at the time. Nick tirelessly developed Tk for over a decade."  
Tcl isn't mentioned even once in the article or its comments.
I guess the charitable interpretation is that "Tk" is meant as the name of the 
Perl module which he did develop, not the like-named GUI toolkit with which it interfaces.
PYK 2014-04-02:  According to the 
Perl page, though, he did actually hack on Tk itself quite a bit, producing a fork that didn't require Tcl, which was then used by 
Perl/Tk.  Also, in the article, "Tk" refers to the Perl module.