I think it would be really interesting and build onto the experience of the game to have the handbook fill out as you discover new items, biomes, creatures, etc. Making it more like a journal of your characters adventures through the world. Maybe make it this old mysterious book you found with a few beginner guides and crafting recipes with plenty of room to expand. I also think in multiplayer this would be a cool way to promote exploration. Especially if you make a system where you can share pages of your handbooks with your friends for things they haven't discovered (with credit to the player who originally discovered whatever of course).
Related to this but it might be way too far out there to be possibly done or just too stupid. As part of this new handbook idea I propose a system that would let you save screenshots on blank pages and add journal entries (with the screenshots being turned into more simple drawings somehow).
It is currently 2am and this was just an idea that has been keeping me and I wanted to share. I would love to see what people think about it and what they would add to/change about my idea.