On this page I, vigal, would like to present my own personal fresh look at Tcl as well as suggest a potentially fresh look at Tcl in general. This will be a work in progress for some time, hopefully not long.
Initially I met Tcl in 1996 after a year of intensively using Perl. When I met Perl, it too was new to me but I learned it quickly from the quick reference at first and more from manuals, books and mainly personal experience over time. So I used Perl for a year and loved it. Then I got ownership of a C-library that was intended to serve as an essential building block for multiple newly planned C-applications. Naturally I wanted to expose it to Perl so it could be used from Perl too. However, and I don't remember why, I got stuck. For some reason, integrating that library into Perl just didn't want to work out. At that point a peer recommended me to try Tcl. It took me maybe a week to read the book, learn the basics and perform the initial integration. And the rest is a whole separate story. Suffice to say that I became a Tcl devotee.
I would like to emphasize that there was nothing special in my learning experiences. They were just more or less what everybody I ever knew had. And although Tcl was easier to learn than Perl, learning Perl wasn't hard either. In any case, the key to learning, any learning, is first of all a good documentation. Also, there is a clear distinction between learning and becoming an expert. While learning can even be just theoretical, expertise only comes with personal experience.
And as for that other story I mentioned, at least as for using Tcl, Scripting: Higher Level Programming for the 21st Century , which I read just this week, describes most of it quite nicely. And in a way, 7 Reasons the Future of Tcl is Bright also touches it somewhat. In any case, both are highly recommended reading.