This is an in-depth study of a vital and fascinating aspect of ancient Egyptian religion as preserved in the Pyramid Texts of the Fifth Dynasty. The creative and life-giving powers of the waters that sustain this world are also present in the Egyptian underworld and enable the dead king who has lived in Truth (Maat) to live again in the endless cycles of nature: the journeys of the sun and the stars and the birth and growth of vegetation. Concepts such as the Winding Waterway, the Great Lake, the serpent and the abyss were used to describe both the dangers of the underworld and the process of regeneration.The examination of water imagery in the Pyramid Texts is set within the context of a description of the essential nature of ancient Egyptian religion and its key concepts. The ultimate value was not the gods but Maat, which may be translated as Truth, Justice, Righteousness and Natural Law. Although other ancient cultures such as Greece and Mesopotamia had concepts of the underworld that included various bodies of water, the Egyptians differed from these in that they believed these waters provided revitalization to become part of the natural cycles of this world.