Some wood, some oil and some tooling and you can be done in no time.
*not so useful for e-books, not there's anything wrong with e-books.
Step 1: Materials and Tools
Drill or Drill Press
Forstner bits. A type of drill bit. You might be able to make do with standard twist bits but the forstner bits allow you to easily and safely drill overlapping holes which is nice for making an oval thumb hole.
Sand paper of various grits
Dremel with sanding bits: (optional but SO useful. a bench sander would be helpful for the outside curve but the inside curves would be problematic.)
Some paper and pencil.
Olive or mineral oil.
Step 2: Design
The hardest part or this step is cutting out the thumb hole. it's fairly small. take this time to get it roughly the right size for your thumb by unfolding, trying it on, and then cut out a little more until it's big enough. You cant make the hole smaller butg you can drill a smaller hole in the wood later so don't stress. Just get it close.