Martin MacInnes's 'In Ascension' is a visionary science fiction novel that follows marine biologist Leigh, from her investigation of an unfathomable ocean trench to the farthest reaches of space. When Leigh's research vessel encounters something unprecedented in the deep ocean, organisms that seem to predate life on Earth, she becomes caught up in discoveries that challenge everything science knows about our origins. The novel spirals outward from oceanic depths to orbital stations to interstellar travel, while spiraling inward into Leigh's consciousness, her memories of a difficult childhood, and her struggle to connect with others. MacInnes writes with literary precision about scientific concepts, making the novel's speculative elements feel grounded in real research while retaining a sense of wonder. The book asks large questions about human purpose, our place in the cosmos, and what it might mean to encounter truly alien intelligence. MacInnes is particularly strong on the subjective experience of profound discovery, the way paradigm-shifting knowledge transforms the self that receives it. Readers who enjoyed the philosophical ambitions of writers like Stanislaw Lem or the contemporary climate fiction of Amitav Ghosh will find a work of similar scope and intelligence.