I read --

1. Principles of Economics by nostr:nprofile1qqsyx708d0a8d2qt3ku75avjz8vshvlx0v3q97ygpnz0tllzqegxrtgpzpmhxue69uhkummnw3ezumt0d5hsvge3uc

2. Economics in One Lesson.

Very simple and got a very good understanding.