That Is All (book)

That Is All is a science fiction novel by American author John Scalzi, published in 2023. It forms part of the Interdependency series, serving as the concluding book in the trilogy after The Collapsing Empire and The Consuming Fire.

The novel resolves the overarching narrative concerning the impending collapse of the Flow, the extra-dimensional pathways that connect humanity's interstellar civilization. It follows the intertwined fates of characters introduced in the previous books, including Emperox Grayland II, Kiva Lagos, and Marce Claremont, as they struggle to ensure humanity's survival in the face of planetary isolation. The central themes explored in That Is All include leadership, sacrifice, adaptation, and the potential for human ingenuity to overcome seemingly insurmountable challenges.