“Question & Answer”

Question:
What title is given to the second part of the book of Isaiah?
Answer:
Deutero-Isaiah, or 2nd book of Isaiah, has come to be the conventional designation for Chapters 40-66. Some scholars discern further refinements, confining 2nd book of Isaiah to Chapters 40-48, with Chapters 49-55 regarded as a post-exilic appendix, and Chapter 56-66, sometimes called Trito-Isaiah, or 3rd Isaiah, as belonging to the age of Ezra and Nehemiah.