As the God of the earth, Geb was one of the most important of ancient Egypt's gods.  According to the Heliopolis doctrine, he came from a line of important gods. His parents were Shu, the god of air, and Tefnut, the goddess of moisture, who were in turn the children of Atum. Osiris, Isis, Seth and Nephthys were the children of Geb and Nut, and together these gods made up the Heliopolitan Ennad. However, it should be noted that Geb may also be referred to in various literature as Seb, Keb, Kebb or Gebb. After Atum, the four deities (Shu, Tefnut, Geb, and Nut) established the Cosmos, whereas the second set of deities (Osiris, Isis, Seth and Nephthys) mediated between humans and the cosmos.

Geb is usually represented in the form of a man who who wears either the white crown  to which is added the Atef crown, or a goose. The Goose was his sacred animal and symbal. As the God of earth, the earth formed his body and was called the "house of Geb," just as the air was called the "house of Shu," and the heaven the "house of Ra," Hence,. he was also often portrayed laying on his side on the earth, and was sometimes even painted green, with plants springing from his body. Earthquakes were believed to be the laughter of Geb.

In hymns and other compositions he is often portrayed as the erpat, i.e., the hereditary, tribal chief of the gods, and he plays a very important part in the Book of the Dead. Therefore he is one of the gods who watch the weighing of the heart of the deceased in the Judgement Hall of Osiris.. The righteous who were provided with the necessary words of power were able to make their escape from the earth  but the wicked were held fast by Geb. 

Religious texts show that there was no special city or district set apart for the god Geb, but a portion of the temple estates in Apollinopolis Magna were called the "Aat of Geb," and a name of Dendera was "the home of the children of Geb,". The chief seat of the god appears to have been at Heliopolis, where he and his female counterpart Nut produced the great Egg from which sprang the Sun-god under the from of a phoenix. In ancient Egypt, the egg is a symbol of renewal, and even today, this symbolism appears in our traditions surrounding Easter.

It was claimed that Heliopolis was the birthplace of the company of the gods, and that in fact the work of creation began there. In several papyri we find pictures of the first act of creation which took place as soon as the Sun-god, by whatsoever name he may be called, appeared in the sky, and sent forth his rays upon the earth. In these papyri, Geb always occupies a very prominent position. He is seen lying upon the ground with one hand stretched out upon it, and the other extended towards heaven Shu stands by his side, and supports on his upraised hands the heavens which are depicted in the form of a women whose body is covered with stars.  She is the goddess Nut. 

In Greek (Ptolemaic) times, Geb became identified with the Greek god Kronos.