Public domain works have already been covered in previous posts, which are accessible by clicking the "Common Ground" label at the bottom of this post.
The Citizen and the State
1984 and Animal Farm, George Orwell
The Fountainhead and Atlas Shrugged, Ayn Rand. Rand's philosophy of Objectivism at Wikipedia.
The Gulag Archipelago: Abridged, Aleksandr Solzhenitsyn. This is a multi-volume work, but I have linked the author-approved abridged version. The original version appears to be out of print, but you can find used copies at Amazon.
Starship Troopers, Robert Heinlein
Economics in One Lesson, Henry Hazlitt, the Henry Hazlitt page at the Mises Institute with essays. A simple, well-written introduction to macroeconomic principles. This was the textbook used in my freshman economics course. It has gained a reputation as a libertarian or conservative work, but the field of economics leans that direction. There are websites that have put the book online in digital format for free, but as far as I know it is still under copyright and they are not legally sharing it, so I have not linked them.
A Monetary History of the United States: 1867-1960, Milton Friedman and Anna Jacobson Schwartz, summarized at Wikipedia. This book argues that monetary policy profoundly influences a nation's economy. One of the more interesting parts of this argument is their claim that the Federal Reserve's monetary policy was responsible for the severity and length of the Great Depression. That has been a controversial claim, but they make a good case.
The Mystery of Capital: Why Capitalism Triumphs in the West and Fails Everywhere Else, Hernando de Soto
The Road to Serfdom, Friedrich Hayek, the Wikipedia page on the book
The Worldly Philosophers: The Lives, Times, and Ideas of the World's Great Economic Thinkers, Robert L. Heilbroner. According to Amazon, this is a "bestselling classic that examines the history of economic thought from Adam Smith to Karl Marx."
Hundred-Year Marathon: China's Secret Strategy to Replace America as the Global Superpower, Michael Pillsbury
The Latin Americans: Their Love-Hate Relationship with the United States, Carlos Rangel
A Mosque in Munich: Nazis, the CIA, and the Rise of the Muslim Brotherhood in the West, Ian Johnson. Grim suggests it "for understanding the roots of the relationship between the US executive, especially the CIA, with the Muslim Brotherhood."
Promised Land, Crusader State: The American Encounter with the World Since 1776, Walter McDougall
Unrestricted Warfare: China's Master Plan to Destroy America, Qiao Liang and Wang Xiangsui
The U.S. and Mexico: The Bear and the Porcupine, Jeffery Davidow. Grim recommends it as "a work by a career diplomat that helps us understand many of our relationships with smaller countries that resent being in America's shadow, but who still need us."
The Radicalism of the American Revolution, Gordon S. Wood
The Weight of Glory and Present Concerns: A Compelling Collection of Timely, Journalistic Essays, C. S. Lewis
Ten Universal Principles: A Brief Philosophy of the Life Issues, Robert J. Spitzer
Happiness is a Serious Problem: A Human Nature Repair Manual, Dennis Prager
In some cases, authors were mentioned without specific works. I've decided to link the Wikipedia pages for them here.