Along the central section of the ceiling, Michelangelo depicted nine scenes from the Book of Genesis, the first book of the Bible. The pictures fall into three groups of three alternating large and small panels. The first group shows God creating the Heavens and the Earth. The second group shows God creating the first man and woman, Adam and Eve, and their disobedience of God and consequent expulsion from the Garden of Eden where they have lived and where they walked with God. The third group of three pictures shows the plight of Humanity, and in particular the family of Noah.
The pictures are not in strictly chronological order. If they are perceived as three groups, then the pictures in each of the three units inform upon each other, in the same way as was usual in Medieval paintings and stained glass. The three sections of Creation, Downfall and Fate of Humanity appear in reverse order, when read from the entrance of the chapel. However, each individual scene is painted to be viewed when looking towards the altar. This is not easily apparent when viewing a reproduced image of the ceiling, but becomes clear when the viewer looks upward at the vault. Paoletti and Radke suggest that this reversed progression symbolises a return to a state of grace. However, the three sections are generally described in the order of Biblical chronology.