George Washington and Abraham Lincoln are honored for doing entirely different things: Washington because he successfully carried out a war for independence, Lincoln because he successfully crushed a war for independence. As in these two outstanding instances, a principle absolutely correct within certain limits may not be so under other conditions. In the field of public affairs and social relations, principles equally good in their place often come into conflict; and it is there that the student of political science finds his most interesting problems. President Lowell has observed such conflicts with the wisdom that comes from long experience and has discussed them in a book that will stimulate thought, arouse discussion, and lead to a reconsideration of many questions.