It’s probably “Rich Dad, Poor Dad”. If you’re interested in any personal finance book, there is already nothing to learn.

None

I always choose hardcover. I try to keep the number of my owned physical books low. So when I do buy it, I want my eyes to be satisfied and they prefer the looks of hardcover. Since I usually buy secondhand books, overall it’s very cheap (although I don’t have high standards on the book’s condition).

Parts Unknown

I use mainly fish and occasionally nushell.