Ideal as a brief main text for IR Theories courses or as a supplemental text for IR, American Foreign Policy, or Global Studies courses, International Relations Theory: A Primer, Second Edition, covers the main definitions, concepts, arguments, and criticisms regarding the five predominant IR theories and approaches used in the field today: realism, liberalism, constructivism, economic structuralism, and feminism. Bridging the gap between theory and practice, it helps students understand and critique the theories and apply them to real-world issues.
I'm sure if it counts to include a textbook but I'm doing it anyway because I learned so much and thought alot about the world while I read this. (especially nuclear weapons and disarment!)