There's a copy on Github nevertheless -
<a href="https://github.com/diveintomark/diveintopython3" rel="nofollow">https://github.com/diveintomark/diveintopython3</a>
Try Wayback machine when site is offline to retvieve information
<a href="https://web.archive.org/web/20181009120324/http://www.diveintopython3.net/" rel="nofollow">https://web.archive.org/web/20181009120324/http://www.divein...</a>
Dive into Python 3 is a really good book. Although there are better books for learning the nuts and bolts of python, dive into python taught me noy just python, but also a lot about character encodings and why understanding them is important.