Interesting in parts but I didn't love it. I was hoping it would mostly be historical anecdotes about important codes and how they were (or weren't) broken and how that affected history. There was SOME of that, and it was always really good. But then he often gets really deep into the weeds about how to break certain types of cyphers, which was not interesting to me, and the last half of the book is all about email security and RSA and PGP and quantum computing, which was also not what I was looking to this book for. So it was good and I'm glad I read it but it's maybe best for people who really want technical background on this stuff, more than a historical survey.