The main topic of the book is the miscarriage of justice and the exposure of corruption and antisemitism within the French military and government. The content of "J'accuse...!" takes the form of a direct address to the French President, Félix Faure, in which Zola systematically lays out the facts and the chain of responsibility for the wrongful conviction of Dreyfus. Zola accuses key military officials and experts of deceit, collusion, and incompetence, asserting that Dreyfus's conviction was engineered through a mix of fabrications, prejudice, and the protection of institutional interests. He denounces both the secretive judicial process and the campaign of misinformation orchestrated by the army’s leadership. Throughout, Zola demands accountability and insists on the unstoppable march of truth, courageously risking prosecution for defamation to prompt justice and reform. The letter stands as a powerful call for justice, enlightenment, and the protection of individual rights against institutional wrongdoing. (This is an automatically generated summary.)