The struggle for power
Throughout the book, a number of different characters and organizations struggle for power. They struggle for different kinds of power, whether it be on a personal, governmental, or interplanetary. This theme is especially prominent in the conflict and impending war between Earth, Mars, and the Belt, each of whom want to control as much of the solar system as they can. They also want power so that they can be independent and control themselves and their government.
The impact of war
The book explores war and its devastating and wide-ranging impacts, both on individuals and on entire societies and planets. The characters must come to terms with the losses and sacrifices they have made and weigh the cost of their actions. People around them die, are maimed, or have their lives and relationships changed forever. But the impact of war isn't isolated to only personal things; it impacts planets ecosystems, governments, and economies.
The will to live
Throughout Caliban's War, characters are constantly faced with challenges and other threats their lives and resolve which test their determination to survive. In different ways, each character in Corey's novel struggle to survive because of the hostile environments they find themselves in but, because they have a will to live, continue on. Those who live on Ganymede, for instance, struggle every day with the difficult conditions on their planet and must have a profound will to live and a will to survive. They do difficult things to survive and to protect their own families.
