A must read for any new-comer to the subject of international relations. Topics covered are varied and relevant. Very applicable to today's world.

System Effects, by Robert Jervis, is an exploration of how the complex relationships between nations can generate or constrain action. Because each nation has its own goals and methods, it will try to seek the best situation. The problem is, because each nation has neighbors and opponents, it cannot always act precisely how it wants.

Jervis deals with three basic types of problem:
1) You cannot predict the total effect from individual effects. That is, although each policy you adopt might have a certain goal, some might backfire or feedback in unpredictable ways. An international example is the Trident missile: our goal was to get a more accurate second-strike capability to deter the Soviet hope for a first-strike success. However, their accuracy was so high that the Soviets perceived the Trident as a first strike weapon. Combined with the accuracy of the land-based missiles, it looked to some in the USSR that the US was planning for a first strike. This result is not predictable when you consider the land and sea based policies in isolation, or by simply assuming that your overall increase in accuracy has a deterrent effect. By making the Soviets more nervous, our policy may have increased the chances of war.

2) Your behavior depends in part on the behavior of others. One nation may seek peace, but it cannot disarm if its opponents pursue war. Alternatively, if your opponents follow a course of appeasement, you may continue in actions as an aggressor.

3) Your actions reshape the world in which you live. As you defeat one opponent, another may encroach on his territory and become a new threat. If you choose to disarm, others may perceive you as less threatening, and also disarm.

Jervis' account is detailed, but his writing style is a bit long-winded. I would have preferred more examples and less theory. Another problem is that the systems approach to international relations doesn't help you much: you can understand history, but because of the three effects he explains, you can't predict the future. Knowing about feedbacks and high order effects can make you cautious, but it can't inform you actions to a high degree.

I recommend this book for historians and strategists, but urge them to seek other sources for information on more concrete policy.