Essential Coding Theory [pdf]

Another good, recently created text is Information Theory: From Coding to Learning.

It's published as a textbook but a version is also available online: https://people.lids.mit.edu/yp/homepage/data/itbook-export.p...

Same for David MacKay's Information Theory, Inference, and Learning Algorithms https://www.inference.org.uk/itprnn/book.html

The video lectures are excellent too. Anyone interested in this stuff could do far worse than start here (though a little dated now - fundamentals fine though)

https://www.youtube.com/playlist?list=PLruBu5BI5n4aFpG32iMbd...