Cryptonomicon is a story about cryptology, WWII, and generational legacies. The book plays with time in its storytelling, jumping back and forth two generations in its action. It also contains multiple main characters, whose lives intertwine throughout the narrative.
One of the main characters is an individual who knows a lot about UNIX, and his knowledge is sprinkled into the narrative. As a linux user, I liked that aspect of the story a lot. I also appreciated the diagrams and drawings that are tastefully employed throughout the book. I'm that kind of visual person and it reminded me of my own desperation to find a white board as I attempt to explain concepts.
The one criticism I would have of the book is that the language is clever in a way that can be slow reading at times. Sometimes a writer's style can flow in a way that causes the book to be easily consumed, such as in the case of King, Grisham, or Vonnegut, but Stephenson is not one of these kinds of writers. Each character has a very strong voice, and it can be a bit jarring to follow the constant transitions in the book.
The book is a generous 900+ pages, made even more dense by its lack of chapters or sections. After reading the entire wheel of time series this doesn't seem so huge to me, but it is a pretty long book.
I definitely dug this book a lot and would recommend it to anyone who is into a bit of technology or science-fiction in their reading material.