A foundational text of science and technology studies from the field’s most celebrated theorist. Science and technology have an immense impact on every aspect of society, but how exactly are scientific facts produced? In this lively and authoritative classic, Bruno Latour reveals that social context is as important as technical content when it comes to understanding how science works. Latour’s focus is not on what scientists say but on what they do, from the day-to-day practice of gathering data and writing technical papers to the travel and networking required to secure funding. Observing the scientific enterprise with the analytical distance of an ethnographer participating in a foreign culture, he argues that science is driven not by value-neutral discoveries of objective truths and natural laws but by the elaboration of longer and stronger networks encompassing both people and things. Only by mobilizing a wide range of human and nonhuman actors—fellow scientists, bureaucrats, specimens, instruments, calculation devices, texts, microbes—can “fact-builders” successfully accumulate the authority needed to convert a novel, tendentious claim into an accepted truth. Setting a pioneering agenda for the social studies of science, Science in Action marshals a wealth of vivid examples to challenge conventional disciplinary boundaries and introduce readers to the disorienting conceptual universe of actor-network theory. Playful, irreverent, and unremittingly provocative, it remains among Latour’s most significant works.