"Cosmonaut Keep" is a page-turning, memorable and enchanting start to Ken MacLeod's "The Engines of Light" space opera science fiction series of novels, successfully recycling such time-worn tropes of science fiction like first contact and the role of computerized technology in a near future human civilization. MacLeod courageously takes us on a centuries-spanning journey through time and space as seen through the eyes of 21st Century outlaw freelance computer programmer Matt Cairns and his direct descendant, Gregor Cairns, an exobiology student and citizen of the remote human colony world of Terra Nova. Cairns is assigned the task of breaking into the computer network of the secret European Space Agency space station Marshall Titov, soon after a mutiny occurs, with the station's scientists seizing control of it from the station's military crew, shortly after making First Contact with an alien race possessing the secret to interstellar travel. Cairns finds himself confronted unexpectedly with his family's historical legacy, even as he tries to woe the daughter of a young trader, not realizing that his research partner Elizabeth has fallen in love with him. Together, with the assistance of their alien Saurian friend Salasso, they seek discovering again, the secret to interstellar travel. This is a novel rich in fantastical imagery, from the arrival of a gigantic starship to stumbling upon the surprisingly rich, almost human, family life of Salasso and his Saurian family and friends. Though MacLeod is a gifted storyteller and a fine prose stylist in his own right, readers should prepare themselves for the frequent, quite substantial, jumps in space and time as he shifts his focus from Matt Cairns to Gregor Cairns; that, however, is merely a minor criticism for what I regard is among the most intelligent, well-conceived, and well-written space opera science fiction in contemporary Anglo-American science fiction literature.