Isaiah is a prophetic book, notable for being one of the most cited texts in both Jewish and Christian traditions. Most of the texts in this book are poetry, often of a highly complex and elusive sort. It is sometimes not clear where a particular prophecy begins and ends, and, especially in the first half of the book, one can sometimes debate whether a passage intends to comfort or castigate the nation. it is best to approach the book as a collection of texts or an anthology, in which each passage demands careful attention, thinking, rereading, and contemplation.