Job is the 18th book of the Old Testament and the 1st book of poetry. It has 42 chapters. In the Hebrew Bible, Job is part of the כְּתוּבִים (Ketuvim, or Writings).
Job probably lived around the time of the patriarchs (Abraham, Isaac, and Jacob). If this is the case, the events of this book took place within 200 years or so of 2000 BC. The book itself, however, was not necessarily written during this time; many scholars believe it was put in its final form around the time of King Solomon.