Previous editions have been available from Internet Archive. https://archive.org/details/mastering-bitcoin-by-andreas-antonopoulos.

To Andreas' great credit, I believe they were sanctioned by the author himself to be free to download.

He's always been a great Bitcoin ambassador.

I don't hear from Andrea Antonopolous nowadays but his book is still the best you can read about Bitcoin

Can you get this one too? https://amzn.to/3TfYSKZ

awesome