The philosophical differences in Theodore Roosevelt and Woodrow Wilson’s approaches to foreign policy are highlighted in this lecture outline. The intellectual traditions (e.g., Aesop’s Fables and Book of Isaiah) of both presidents are briefly discussed as a means of introducing broader themes, key terms, and historical events. Key terms include the following: optimism, pessimism, realism, idealism, balance of power, realpolitik, messianism, collective security, national interest, and spheres of influence. Each is illustrated with examples from the dawning of the twentieth century. The lecture outline concludes with sources for further study.