Baal means "lord" or "owner" and refers primarily to the Canaanite fertility god. This god, one of many Canaanite deities, was thought to control fertility—of man and especially of crops— through the sun, rain, and all types of weather. As Mrs. Eddy explains in Miscellaneous Writings: "The worshippers of Baal worshipped the sun. They believed that something besides God had authority and power, could heal and bless. . . ."
Baal was a dying and rising god, representing the conflict in nature as seasons and harvests come and go. Worshipers believed they could control the actions of Baal by humanly mimicking him—by sacrifices, sexual ceremonies, and imitative magic. In his Understanding the Old Testament, Bernhard W Anderson illustrates the distinction between Baal worship and worship of God (Yahweh): "While Baal religion taught worshipers to control the gods, Israel's faith stressed serving God in gratitude for his benevolence and in response to the task which he lays upon his people."
When the children of Israel were led by God into Canaan, they naturally did not enter a vacuum. They went from a nomadic existence where they'd learned to worship one God, Yahweh, into a settled, agricultural land where people obeyed many gods.