As far as economics is concerned, I recommend Mankiw's principle of economics. It's widely used as a textbook for economics undergraduates. It's very well written and entertaining. In my opinion, it's better than general public vulgarization books.
Mankiw's books is the best option if you want an inferential and qualitative understanding of the subject. If you want something with more mathematical rigor I suggest Blanchard's Macroeconomics.
