The Classics of Political Economy
These are texts that examine the political economy of trade, including the rationale for (and sometimes against) free trade as well as the contentious relationships between trade, democracy, war, peace, and development.
The starting point for the field, and for any reader, is Adam Smith's An Inquiry into the Nature and Causes of the Wealth of Nations (1776). Remembered by most for brief phrases (especially "the invisible hand") or explanatory descriptions (e.g., the division of labor in the manufacture of pins), this classic is a much more far-ranging analysis that will alternatively surprise, amuse, or provoke the careful reader. It merits thorough and careful review not just for its original insights but also as an examplar of clear writing and persuasive prose.
Plutarch, "Lycurgus," from The Lives of the Noble Greeks and Romans (75 A.D.)
Niccolò Machiavelli, Discourses on the First Ten Books of Livy, Book II, Chapter 10 (c.1517)
Bernard Mandeville, The Grumbling Hive — or — Knaves Turn'd Honest (1705)
Adam Smith, An Inquiry into the Nature and Causes of the Wealth of Nations (1776)
James Madison, papers on factions (1788)
Thomas Jefferson, Report on the Privileges and Restrictions on the Commerce of the United States in Foreign Countries (1793)
Friedrich List, The National System of Political Economy (1841)
Richard Cobden, On War, Peace, and Free Trade (1846)
Karl Marx, On the Question of Free Trade (1848)
Vladimir Ilyich Lenin, Imperialism: The Highest Stage of Capitalism (1916)
John Maynard Keynes, The Economic Consequences of the Peace (1919)
UNCTAD, Towards a New Trade Policy for Development (1964) [Note that this is a large PDF file.]