Amos and Hosea are the first two prophets who get their own books. They are also the last of the four northern Israelite prophets. Amos is the perfect prophet, the template for all later prophets. He launches a socialist critique on the Israelite upper-classes, and calls on the people to be righteous, and not just rule-followers. Hosea uses uncomfortable crazy sexual imagery to denounce the Israelites' worship of Baal. Hosea is nuts.