Joe
In many ways, Symbolism is the Fourth Gospel: Meaning, Mystery, Community, feels like a commentary. That is how I use it. In saying this, I mean that it is not a book I read from cover to cover. Rather I turn to it when I want to delve into a specific portion of Scripture. That said, while it is used like a commentary, it does not present itself as one.
Koester does not organize in a verse-by-verse format. Nor does he journey through the text through linear expository sections. Rather, he arranges his work thematically. Themes include representative figures, symbolic actions, light and darkness, water, and the crucifixion.
This is particularly helpful with John who also weaves themes together throughout his work. By mimicking the style of the author, Symbolism in the Fourth Gospel, invites the reader to think about the whole of John. We learn to see the book as a tapestry of signs, feast days, and symbols. These themes open as the Word appears. They remain till the crucified and resurrected Word made flesh commissions the disciples to continue the work.
In the tasks of preaching and teaching, this allows for a fuller and more contextual message. It invites the reader into the very heart of John, a Gospel that feels simple while abounding with complexity.
That is why Symbolism in the Fourth Gospel is the first resource I turn to whenever I work with the Gospel According to John.