Douglas A. Irwin, "Three Simple Principles of Trade Policy"

You can find it here. It's almost 30 years old, but (sadly?), the lessons are relevant for today. Irwin explains, clearly and succinctly, three things that everyone needs to know about international trade: "a tax on imports is a tax on exports," "businesses are consumers too," and "trade imbalances reflect capital flows." He explains the principles and their intellectual history, explaining that these are pretty resilient propositions that have been tried in many fires. If you're looking for a good read on international trade, I highly recommend it.