This isn't a puzzle game for the easily stumped or for those looking for in-game mechanics. I copied everything in the book into a notebook to write my own notes all over it, only the one thing that triggers completion requires you have the game open or lets you know you solved the final puzzle. That aside, this is a delightful cryptography-based and pseudo-historical puzzle game. I would definitely recommend having at least a cursory knowledge of ciphers before buying, but it's a fun little book of head-scratchers that can cause a few of those "eureka" moments.