This was a fun read! I really liked how it was a sneaky (maybe not so sneaky) ode to programming, books, and typography. I liked all of the characters and thought that they were well-developed. The first-person narration style wasn't really my thing but I still mostly enjoyed hearing Clay's inner thoughts and witty, sarcastic silent interjections. Penumbra! What a mysterious fellow. He is just who I like to imagine running old and dusty workshops. He was just missing some half-moon spectacles, I think. Kat was cool, I liked that she was pretty fierce and also obviously very intelligent. My favourite part of the book was when **SPOILER** the Googlers were trying to break the code. I thought this part of the story was written very cinematically, and I got really excited while they were trying to figure it out and even more-so when Kat put it to the "whole system". I was then thoroughly disappointed to find out that nothing was there but I had to say, I saw it coming. Also, since we are on the topic of spoilers, I felt so immersed and connected to the story when Clay cracked the mystery, finally. Gerritszoon! **SPOILERS OVER**So all-in-all, this was a great, fun, quick read. It lost a star for me, for the narration style as well as the fact that it took a while for me to really care about the mystery.