
Book of Isaiah, or Isaiah is the first of the Latter Prophets in the Hebrew Bible and the first of the Major Prophets in the Christian Old Testament. It is identified by a superscription as the words of the 8th-century BCE prophet Isaiah ben Amoz, but there is extensive evidence that much of it was composed during the Babylonian captivity and later. The consensus through most of the 20th century, that the book comprises three separate collections of oracles: Proto-Isaiah (chapters 1-39), containing the words of Isaiah; Deutero-Isaiah (chapters 40-55), the work of an anonymous 6th-century BCE author writing during the Exile; and Trito-Isaiah (chapters 56-66), composed after the return from Exile. While virtually no scholars today attribute the entire book, or even most of it, to one person, the book's essential unity has become a focus in current research.

Suffering, or pain in a broad sense may be an experience of unpleasantness or aversion, possibly associated with the perception of harm or threat of harm in an individual. Suffering is the basic element that makes up the negative valence of affective phenomena. The opposite of suffering is pleasure or happiness.
Suffering is often categorized as physical or mental. It may come in all degrees of intensity, from mild to intolerable. Factors of duration and frequency of occurrence usually compound those of intensity.