Comprising twelve essays and an engaging introduction, this volume places instruments and technology at the heart of modern exploration and associated sciences. The chapters form three clusters, distinguished by era and theme. The opening four have a distinctly maritime feel, focusing on the instrumental practices of the globally expansive Royal Navy from the mid-eighteenth century to the mid-nineteenth. The middle four form a looser suite, discussing issues of collection, lending and display. The final four look to the sky, analysing the co-constitution of technologies and spaces of exploration, knowledge and war during the twentieth century.

What ties these varied contributions together? Perhaps most importantly for historians and philosophers of science, all engage with the notion of instruments as things that ‘perform’ within mutable assemblages comprising heterogeneous elements. Intersections and tensions between humans and their materials – or between materials and their humans – in situations ranging from the Arctic Ocean in the 1810s to British airspace in the 1960s produce fruitful dissensus on the activity or passivity of material objects. Some chapters present instruments as agglomerations of practices and discourses; others claim that the functioning of hardware had substantial impacts on theoretical developments. Taken as a whole, the book extends and nuances work by Davis Baird and Lorraine Daston by showing how matter and meaning interplay in almost limitless variations.

Many of the volume's authors also consider the related question of what constitutes an instrument. Claire Warrior and John McAleer ask us to think of oil paintings and banjos as instruments of exploration; other contributors include notebooks, ledgers, and writing materials among their instrumental repertoires. Such debates build on Richard Sorrenson's pioneering notion of the eighteenth-century ship as instrument, prompting readers to assess the prospects and drawbacks of adopting capacious definitions of ‘instruments’ and ‘technologies’.

With the notable exceptions of Deborah Warner's globe-spanning account of seismography, the portion of Simon Naylor's chapter on the spread and limitations of a single ‘meteorological culture’, and Fraser MacDonald's reading of Cold War-era American rocketry, British institutions, instruments and personnel are in the spotlight throughout. More studies centring on other global powers would have opened comparative opportunities and allowed for an assessment of the degree to which nineteenth-century exploration was a British-led phenomenon. However, the essays do serve to show how instruments and their wider assemblages are forged through myriad far-flung and unpredictable encounters. Warner's chapter in particular brilliantly analyses the multiple spatial scales that both influence and coalesce around objects of measurement. The volume convinces us that, even in the heyday of the British Empire, devices did not travel unhindered from core regions to measure and order peripheries. Historians of imperial and global science will welcome the insightful stories of laborious processes of mending and repurposing, ranging from what Eoin Phillips insightfully calls ‘rhetorical repair’ (p. 45) to myriad material manipulations. In this respect, the volume expands on work by Simon Schaffer and Marie-Noëlle Bourguet emphasizing the fragility of instruments, especially when spatially displaced, and deepens Mary-Louise Pratt's and Dane Kennedy's insights on the complexities of producing and disseminating exploration knowledge.

It is not only through such shared features but also through disparities and disagreements that the volume's contributions interact productively. For instance, A.D. Morrison-Low's curatorial doubt over whether a ‘commonplace’ instrument is worth displaying ‘merely by virtue of its associative connections’ (p. 137) jars with the emphasis in most other chapters on what instruments do rather than what they are. It thereby gestures towards a disparity between public demand for visually arresting renderings of famous moments in exploration on the one hand, and, on the other, increasing scholarly attention to multifaceted assemblages of less spectacular objects, quotidian practices and ‘ordinary’ people. The collection's attention to the knotty issue of how fallibility and complexity might be made as appealing as tales of heroism deserves to engage historians of exploration and museum curators alike.

Among the most important contributions this volume makes to existing studies are its fine-grain analyses of situations in which instruments and their associated networks of institutions and interests exhibit an uncanny ability to reproduce themselves. The first and last clusters of chapters compellingly show how technological and instrumental developments, and associated disciplinary innovations and shifts, were entangled with wars and their aftermaths. Richard Dunn and Simon Naylor convincingly link major changes in studies of terrestrial magnetism and meteorology to a Royal Navy without a cause in the wake of the Napoleonic Wars, a reading that resonates with Peter Collier's account of aerial photography in the wake of the World Wars. Other contributors show that technological development can take on a self-perpetuating logic. Isla Forsyth's chapter on camouflage suggests how technologies could prompt the advent of countertechnologies. In other instances, calibrating and assessing instruments, ranging from compact compasses to monumental rockets, often called for a slew of further instrumentation.

In occasional allusions to another form of the uncanniness of technology, the volume also gestures towards a theme that deserves to be prioritized in future studies of instruments and technologies of exploration. While a number of contributions build on Kapil Raj's notion of humans becoming regularized instruments, none fully develops the idea of instruments seeming, through their capabilities and fallibilities, human. Rae, Souch and Withers's chapter goes furthest in analysing the commingling of the corporeal and the mechanical in late nineteenth-century exploration by captioning an image of a Royal Geographical Society ledger: ‘The life and death of explorers and instruments’ (p. 156). Alongside states of disrepair, historians of science should also foreground moments when instruments appeared to be in rude health, performing in multiple ways and even seeming to take on autonomous agency. In cross-cultural encounters mediated by their instruments, as well as in various situations of stress and success, agents of exploration repeatedly assigned material objects, especially complex precision instruments and technologies, ‘magical’ or affective attributes. That self-described ‘moderns’ could be, as it were, more idolatrous than most of their idolaters in their intimate relations with instruments is just one of many areas opened for further exploration in the wake of this enlightening collection.