Who was the god Amon?
Amon (or Amun), in Egyptian religion, was the god of air and wind. He was sometimes invisible, like air. Other times artists showed Amon with blue skin, or as a blue frog - blue like the sky. (Compare Amon with the Indian god Vishnu, who also is sometimes blue.)
Because Amon was the god of air, people also began to think of him as the god of the "ba", or the soul, which is like the breath of life.
In the New Kingdom, the capital of the pharaohs was at Thebes, in Lower Egypt, and that was the main city where people worshipped Amon. So the priests of Amon got very powerful. Some of the pharaohs had names that referred to Amon, like Tutankhamon. One pharaoh, Akhenamon, tried to take power away from the priests of Amon. He renamed himself Akhenaten after the "aten", the sun, and built a new capital city at Amarna. But after Akhenaten died, the priests of Amon got back their power, and the pharaohs moved their capital back to Thebes.
Greek travellers like Herodotus thought of Amun as being like Zeus, and Amun's wife Mut as being like Zeus' wife Hera. But really Amon was an African god, who was also worshipped south of Egypt in Meroe, and in other parts of Africa by the Bantu.
After the Egyptian pharaohs stopped having their capital at Thebes, at the end of the New Kingdom about 1200 BC, fewer and fewer Egyptians worshipped Amon. People in Kush, further south, however, continued to worship Amon until about 200 BC.
Gods and Goddesses of Ancient Egypt, by Leonard Fisher (1999). For younger kids.
The Egypt Game (Yearling Newbery), by Zilpha Keatley Snyder (reprinted 1985). A great kids' story about kids who pretend to be Egyptian gods and goddesses.
Religion in Ancient Egypt: Gods, Myths, and Personal Practice, by John Baines, David Silverman, and Leonard Lesko (1991). Pretty hard going, but it will tell you everything you need to know about Egyptian religion.