Short answers, pulled from the story.
Genesis was written anonymously. Jewish and Christian tradition attributes it to Moses, but scholarly consensus holds that it was composed after the Babylonian captivity, possibly in the 5th century BCE. The documentary hypothesis identifies four distinct source layers: the Yahwist (J), Elohist (E), Deuteronomist (D), and Priestly source (P).
Genesis covers the creation of the world, the early history of humanity including the stories of Adam and Eve, Noah and the flood, and the Tower of Babel, then shifts to the ancestral history of Israel through Abraham, Isaac, Jacob, and Joseph. The book ends with Jacob's family of 70 people settled in Egypt.
Genesis divides into two main parts: a primeval history covering chapters 1-11 and a patriarchal history covering chapters 12-50. The book is also organized internally by the Hebrew phrase elleh toledot, meaning "these are the generations", which appears eleven times and marks transitions between subjects.
Scholar David Clines, writing in 1978, concluded that the overarching theme is the partial fulfilment of the promise to the patriarchs, encompassing offspring, blessings, and land. The Priestly source structures this through a series of covenants with Noah, Abraham, and eventually Moses, each marked by a distinctive sign: the rainbow, circumcision, and the Sabbath.
Four major manuscript groupings survive: the Masoretic Text, the Samaritan Pentateuch, the Septuagint (a Greek translation), and fragments found in the Dead Sea Scrolls. The Dead Sea Scrolls are the oldest of these but cover only a small portion of the book.
Genesis's assertion that humanity is created in the image of God has been cited as a foundational influence on Western concepts of human dignity and natural rights. Religion professor Elaine Pagels connected elements of Genesis to the intellectual background of the United States Declaration of Independence. The book also anchors the first 12 of the 54 weekly Torah portions read annually in Jewish liturgy.