Ba'al from Ugarit
(Louvre Museum, Paris)
All along the eastern coast of the Mediterranean Sea, in what's now Lebanon, Syria, and Israel, and down into the Arabian Peninsula, there was (and still is) a feeling that it's wrong to say the name of your god aloud. Instead, people called their god "Lord".
Baal is the Semitic word for "Lord", so to people who spoke Aramaic, Hebrew, or Arabic Ba'al could mean any male god. People who lived in ancient Phoenicia used "Ba'al" as a name for the god of their own city. Some gods called "Ba'al" were sky gods or rain gods, but many were less powerful local gods.
When the Phoenicians sailed to North Africa and built the city of Carthage, about 800 BC, they brought their language with them, and the Carthaginians also called their main god "Ba'al". In Carthage, Ba'al was the husband of Tanit, the moon goddess.
Early Jews also called their god "Ba'al," or "Lord", but around 600 BC, in order to make it clear that their god was really different from the other local gods, the Jews changed to using the word "Adonai" to mean "Lord".
When Greek people settled in Phoenicia and Israel, in the 200s BC, they thought of Ba'al as being like their god Zeus. But when most people in Phoenicia, Syria, Israel, and North Africa converted to Islam in the 700s AD, they began to call their god "Allah" (the God) instead of Ba'al.
Ancient Mesopotamians, by Elena Gambino (2000). For kids, retellings of Mesopotamian stories and lots of context.
Gods, Goddesses, and Monsters: An Encyclopedia of World Mythology, by Sheila Keenan (2000). Easy reading.
Religion in Ancient Mesopotamia, by Jean Bottero (2001).
God Against the Gods: The History of the War Between Monotheism and Polytheism, by Jonathan Kirsch (2004). From Akhenaten in Egypt, through Judaism and the rise of Christianity. Lively, popular writing.
A World Full of Gods: The Strange Triumph of Christianity, by Keith Hopkins (2001). Entertaining account of what it was really like at non-Christian and early Christian religious events. Not for young kids.