Across the vast expanse of cosmic time, these stories chronicle the rise and fall of civilizations caught in the shadow of the enigmatic Xeelee. The narrative follows various human and post-human entities as they navigate the physical constraints of a universe dominated by dark matter entities and the manipulation of spacetime. Through a non-linear framework, the collection maps the evolution of life from the primordial quagma to the final heat death of the universe. Protagonists must contend with the overwhelming scale of galactic engineering and the existential threat posed by the photino birds, often utilizing advanced wormhole technology to survive or escape their inevitable extinction.

This collection serves as a foundational expansion for readers already familiar with the broader Xeelee sequence. The stories are noted for their rigorous adherence to speculative physics and their focus on the immense scale of cosmic events. Critics often highlight the author's ability to maintain a consistent internal logic across disparate timelines and technological eras. The work is regarded as a significant contribution to hard science fiction, providing necessary context for the larger narrative arc of the series. The prose maintains a clinical and detached tone that emphasizes the vastness of the universe over individual character development.