Isaiah is one of the Bible's most famous texts. In the modern era, it has also become one of the liveliest topics in the historical study of how the Bible was written. Challenging the traditional ascription to Isaiah himself, scholars overwhelmingly regard the book as a composite work that was produced by different people over several centuries. Beyond this basic consensus, however, there is fierce division over the details. The most important disagreement concerns whether the book is ultimately characterized by unity or disunity. Scholars who read the book for unity argue that while it is certainly composite, each layer nevertheless built on and reshaped the previous ones, yielding a purposeful, coherent whole. Scholars who read the book for disunity argue instead that it is a loose combination of self-sufficient texts that need to be interpreted separately. In Unity and Disunity in Isaiah, Ethan Schwartz offers a serious yet accessible overview of this scholarly debate, bringing out its historical, exegetical, and theological stakes. Readers will gain the tools to begin making sense of how this book was written--and how, in turn, it should be read.