There are three main schools in IR:

- Realist
- Liberal (or Idealist)
- Marxist


Within the Realist school are: Classical Realism, Neo-Classical Realism and Neo-Realism.

Within the Liberal school are: Classical liberalism, neo-liberalism.

There's Marxism and neo-Marxism.

The rest, such as Constructivism, functionalism, feminism, etc are not relevant to the CSS course.

I have Palmer and Perkins and Sultan Khan and none of them cover IR theory. But you can find plenty of material for these schools of thought online, especially on Wikipedia.