Website content:
https://ghorwin.github.io/qwtbook
This project attempts to create a sort-of programmers manual to the Qwt library. Work is in progress, but feel free to look at the pages.
The book is currently being written in German but webpage-translators do a great job at translating the text to english or other languages.
Feedback is welcome, either in the qwt-forum on qtcentre, or via github.