Rather than being content with atomistic approaches to a text, recent scholarship has increasingly seen the value of tracing motifs and their variations as they run through biblical books, and even across book boundaries. Williamson takes up the important but inadequately explored messianic theme, tracing its development and variations through the canonical Isaiah. He sets this unifying thematic study against a counterpoint of redactional analysis, which exploits and builds on his previous work in The Book Called Isaiah: Deutero-Isaiah's Role in Composition and Redaction (1994). The current work was composed to serve as the source material for the 1997 Didsbury Lectures at the ^Nazarene Theological College near Manchester, England.

In his introductory chapter, Williamson sets the foundation of his theme against the broader backdrop of the king, which moves from the minor tones of the human, Davidic king in the earlier chapters of Isaiah to the major key of the divine king later in the book. He goes against much recent scholarship in holding that the former derive most probably from before the exile.

The second variation concerns Immanuel, looking in detail at chapters 6-9. He presents and critiques Buddes' century-old hypothesis that Isaiah 6-8 were an Isaianic Memoir which originally opened the book. Rather than taking the call narratives of other prophets as a comparison, Williamson finds closer parallels between the calls of Isaiah and of Micaiah (1 Kgs 22) and the literary shape of Amos 7-8. He sees the chief interest in the Immanuel figure being in fulfilling the role of righteous rule within the Davidic dynasty, rather than in identifying any specific individual.

The third variation, the "Servant" is drawn from Deutero-Isaiah. There the original Davidic relationship with God is transferred to the nation of Israel. She will be God's witness and mediator to the world. As a Christian, Williamson brings up the interpretation that Jesus is the servant according to the NT. He defends his view by stating that "Jesus fulfills, but does not thereby exhaust, the prophecy" (p. 53). The theme of justice and righteousness in association with the servant ties his role to that of the king in the first section.