Science is highly dependent on technologies to observe scientific objects. For example, astronomers need telescopes to observe planetary movements, and cognitive neuroscience depends on brain imaging technologies to investigate human cognition. But how do such technologies shape scientific practice, and how do new scientific objects come into being when new technologies are used in science? In How Scientific Instruments Speak, Bas de Boer develops a philosophical account of how technologies shape the reality that scientists study. We should understand scientific instruments as mediating technologies. Rather than mute tools serving pre-existing human goals, scientific instruments play an active role in shaping scientific work. De Boer uses this account to discuss how brain imaging and stimulation technologies mediate the way in which cognitive neuroscientists investigate human cognitive functions. The development of cognitive neuroscience runs parallel with the development of advanced brain imaging technologies, drawing a lot of public attention—sometimes called “neurohype”—because of its alleged capacity to demystify the human mind. By analyzing how the objects that cognitive neuroscientists study are mediated by brain imaging technologies, de Boer explicates the processes by which human cognition is investigated.