Atlas Shrugged.

Like, a textbook? Or a non-fiction book of some sort?

Any good books that you would suggest. They could be historical books such as some of Adam Smith's work, non-fiction books, textbooks, allegorical novels or anything else in between.

Everything I know about economics is self-taught via reading, so I'll just drop the most useful books I own:

Economics for Dummies.
The Wealth of Nations by Adam Smith.
The General Theory of Employment, Interest and Money by J.M. Keynes (really heavy going).
The Failure of New Economics: An Analysis of the Keynesian Fallacies by Henry Hazlitt.
Austrian Economics: A Primer by Eamonn Butler.
Capitalism and Freedom by Milton Friedman.
Free to Choose, ibid.
The Age of Turbulence by Alan Greenspan.
Boom and Bust Banking: the Causes and Cures of the Great Recession by David Beckworth.
House of Debt: how They (and You) Caused the Great Recession by Atif Mian and Amir Sufi.

I don't agree with the conclusions of every book, but these are very good are introducing you to economics generally and then specific schools within economics.