This document discusses tariff and non-tariff barriers to international trade. It defines tariff barriers as taxes or duties imposed on goods crossing national borders. It outlines various types of tariff barriers including specific duties, ad valorem tariffs, combined duties, and protective tariffs. Non-tariff barriers are any other barriers besides tariffs, such as quotas, licenses, product standards, labeling requirements, and voluntary export restraints. The document provides examples of different tariff and non-tariff barriers and explains how governments use these barriers to promote domestic industries and restrict imports.