Most scholars believe the Book of Isaiah was written by different prophets at different times. Chapters 1–39 are pre-Exilic: that is, before the Babylonian Exile. The remainder (chapters 40–66) is post-Exilic; it is attributed either to an anonymous Second Isaiah (deutero-Isaiah) or, in the opinion of some scholars, chapters 40–59 to Second Isaiah and chapters 60–66 to Third Isaiah (trito-Isaiah).