[adapted from http://touregypt.net/featurestories/celestrialcow.htm]

The central theme of The Book of the Heavenly Cow is mankind's rebellion against the elder sun god, Re, resulting in the punishment of humans by the fiery "eye" of Re in the form of the goddess Hathor. It takes place after Re's long rule on earth. The first part places considerable emphasis on the royal role of the sun god, who bears the royal title and who's name is surrounded by a cartouche. He is specifically given rulership over both the deities and the humans. 

Prior to the rebellion, which required a complete reordering of the world, there had been a golden age where the various deities and humans were both under the sovereignty of the sun god. During this previous age, the sun god had not yet begun his daily course through the sky and the netherworld. Hence, there was no cycle of day and night, nor was there a netherworld and death did not exist. 

When mankind's rebellion took place, the sun god first consulted with the primeval deities, including Shu, Tefnut and Geb but particularly the goddess Nun and Hathor in the Great House in Heliopolis. These gods were to come to Re in secrecy, as not to alert mankind about their meeting. Re then addressing Nu, the father of the first-born gods, told him to give heed to what men were doing, for they whom he had created were murmuring against him. And he said " Tell me what you would do. Consider the matter, invent a plan for me, and I will not slay them until I have heard what you shall say concerning this thing." Nu replied, " You O my son Ra, are greater than the god who made You (i.e. Nu himself), you are the king of those who were created with you, your throne is established, and the fear of you is great, Let shine Eye (Hathor) attack those who blaspheme you. " And Rw said, " Lo, they have fled to the mountains for their hearts are afraid because of what they have said." The gods replied, " Let shine Eye go forth and destroy those who blasphemed you, for no eye can resist shine when it goes forth in the form of Hathor." 

Afterwards, Hathor was sent to inflict her punishment. For three nights the goddess Hathor-Sekhmet waded about in the blood of men, the slaughter beginning at Hensu  (Herakleopolis Magna).. But the sun god took pity on those humans who were left. He saved them by causing Hathor to become drunk on blood red beer. 

Afterwards, the sun god, Re, withdrew to the sky on the back of the celestial cow who is the Goddess Nut transformed. The cow is supported by Shu, the eight Heh-gods along with the Pharaoh. This would account for the importance of the book for the king, who was the "son" and successor of Re, and who withdraws to the sky upon his death, like Re, on the back of the heavenly cow. Now, humankind could suffer death, and so from his position in the sky, Re constructed the netherworld as their realm (third section of book). Within the netherworld, Re placed many serpents that were entrusted to the care of Geb, the earth god. He also sets the moon in the sky and appoints Thoth lord of the moon and deputy over creation. Now, through Thoth, people will know Re.