127 Stefan Helmreich is interested in oceans. He is also interested in the relation between “life forms” and ”forms of life” . In this book he traces and describes networks of culture, economy and society which orient themselves around biological life. However, having found himself within a feld of scientifc research where what counts as biological life is changing, that tracing turns out to be complex. Te stories of this book emerge from the efort to produce an anthropological account able to do justice to these shifts as they appear in the practice of marine microbiology, but also to recognise the many forms of collective life in which marine microbes are active participants. In the second chapter of this text, entitled ”dissolving the tree of life” , Helmreich ofers a general account of a shift in what counts as biological life. Once the scientifc study of the oceans was concerned with species such as marine mammals, fsh, and seaweed, and their ecologies. Tese individual species could be isolated and counted, and they could be individually studied and located at a branching evolutionary moment on the tree of life. Tis genealogical system outlined by Darwin in On the Origin of Species, was borrowed from Victorian practices of family recordkeeping and property inheritance, and it had the beneft of revealing continuous lines of decent which were traceable to common ancestors. Darwin read these lines of kinship as the organising structure of the organic world, and this tree image became at once naturalised and universalised (p.77). Today in the research practices of marine microbiology these same oceans exist (in addition) as profusions of microbes and extremophiles. Scientists now struggle to classify these microbial organisms. Te coherence of the old story is disrupted by the genetic material that these microbes present. Tis material does not appear as a generation-to-generation form of inheritance; rather these microbes exhibit evidence of lateral gene transfer, and the shuffling of genes back and forth with their contemporaries, as they mix up their own and others’ genealogies (p.82). On land this shift in working imaginary occurred several decades ago in the life sciences. It gained impetus with the mapping of the human genome, and was traced as the opening up of new hybrid lives and imploded spatial relations by Donna Haraway (1997). Now in the study of oceans, genetic information is similarly no longer code for the biological specifcity of organisms. Rather biological organisms are taken as revealing patterns of contingent digital arrangement, and as this situation becomes re-naturalised as what has always existed, new patterns of inquiry, utility, ownership, trade and engineering also begin to infuse and support these new oceans and emerging natures. Emerging patterns of practice, capital fow and cultural signifcation, which ramify around this shift, are what Helmreich describes in rich detail through the pages of his book. In doing so he draws upon the many hours spent with marine microbiologists both on and under the sea, as well as in laboratories and at meetings and conferences. He is able to follow lines of interest and signifcance through Stefan Helmreich: Alien Ocean: Anthropological Voyages in Microbial Seas University of California Press: Berkeley, 2012. 464 pages. Book Review Science & Technology Studies, Vol. 26 (2013) No. 3, 127-129