I’ve read Cryptonomicon by Neal Stephenson.
I liked it. It’s very long, about 900 pages and at times forward progress with the plot diminishes to almost imperceptible but for anyone who likes codes and ciphers and especially Kryptos: I would heartily recommend this book.
You just have to read details about Arethusa and Pontifex and the efforts of the characters to crack them to feel a kinship in regards to all of our efforts to beat Kryptos into submission.
The story stitches past and present together in some nice parallels in a way that many books have failed at before. All the loose ends get tied up and the conclusion is decent.
On the negative? Neal writes quite a bit of himself into the book and for better or worse we get treated to discussions of psychological modeling after Lord of the Rings characters,, pop culture hackerisms, discourses on sexuality and various philosophical meanderings. Given the kind of folks who would likely consider Kryptos entertaining… many of us will understand exactly what he is talking about whether we agree or not.
Taken as a whole, the book captures almost every element of espionage imaginable, covers quite a bit of history, describes many ciphering systems and strategies and does it all while keeping a story going.
I’d recommend this book to most with the warning that if you don’t read much it may be a little overwhelming at times.