“The strength of the present volume is precisely that the possible tension between the historical and literary contexts is never fully resolved. Both perspectives commend themselves to the sensitive reader and preacher of Isaiah.
In this one sense, the threefold presentation of Isaiah in the following chapters is itself far more than the result of practical accommodation or mere convenience.
As the reader moves through the historical world of three Isaiahs and three Israels in three distinct periods, the question of unity and coherence in the sixty-six-chapter book is not set aside.
For ultimately the unity of the Book of Isaiah is not to be sought in issues of single authorship or uniform historical setting, but rather in the common witness of all sixty-six chapters to the one God of Israel, Isaiah's 'Holy One,' who casts down raises up, whose justice shapes the cosmos itself, and whose promises extend into a future beyond the horizon of the book's own historical and literary world.” – Introduction.