In Blowback, Johnson lays the foundation for the rest of his series. He tells stories, relating historical events, which illustrate the notoriously unreliable nature of the United States. From illegal operations abroad to deception of its own citizens, the U.S. government has made itself an enemy of all, Johnson believes.
Johnson explains how a "blowback" works. It's a cycle. In the context of the United States, it works like this: The government performs an illegal (or at the very least unethical) action, which is kept top secret. Eventually the truth comes out. Blindsided and powerless, the American public does not possess the correct tools to correct the mistake, so the people overreact. They then support retaliation against the other countries involved. This opens the U.S. back up to retaliation from those countries once more. It's an endless loop.
To Johnson, the question of America's reputation is an easy one. He believes the rest of the world is correct to hate the United States. In this book, he traces a long train of events which shed light on a disturbing pattern of attack and retaliation in America's global relations. This lays the ground for the Johnson's next few books in the series which predict the downfall of America as a global superpower and its eventual total destruction.