J is the oldest of the five authors (J, E, D, P, and R) of the Pentateuch or Torah, the first five books of the Bible, theorized by Biblical scholars. S/he may have lived between 950 and 750 BC, though this dating is in dispute. J is short for Jahwe, the German spelling of Jehovah or Yahweh. J consistently refers to God by the name Yahweh, while other authors use different words.

The writings of J in the Bible are considered by many to be more engaging, interesting, humorous, and human than the work of the other authors. J is the author of the second creation story in Genesis (Genesis 2:4-25) and the famous poetic image of God strolling around in the Garden of Eden in "the cool of the day" (Genesis 3:8). Some also credit J with the story of the warrior woman Deborah in the book of Judges and other parts of later books.

Conservative literary scholar Harold Bloom injected J into the mainstream consciousness with his controversial bestselling work The Book of J (1991), which theorized that J was female.