The Balance of Power in Flux

Essay 2 pages this is the question : The title of the last chapter is “The Balance of Power in Flux.” This concludes Part II of the book which, according to the authors “covers a shorter time span” and “has a more complex story line” than Part I. Discuss why the title, the time span, and the complexity.
the book is :american foreign policy since world war ii “The Balance of Power in Flux.