Neal Stephenson is able to balance the high flight cryptic genius of Pynchon's "Gravity's Rainbow" with the gripping sense of a spy thriller ala David Grisham, which in and of itself is a pretty neat feat. Towards the end of the book, I did feel like some momentum was lost and I had less of those moments where I was completely enthralled by wondrous mathematical genius and more moments where I was questioning the need for inclusion of slightly cheesy action/romance plot material. But overall, this is a brilliant book on cryptanalysis that scatters its narratives through a web of time and a cast of interesting characters. Quite enjoyable. I'm looking forward to reading more of Stephenson's books.