Tropicality was never a single script nor an 'already fully formed, ready-to-be-projected' discourse (Driver & Martins, 2005: 5) and is best understood as a 'transactional' process of exchange between 'temperate' and 'tropical' peoples, places and experiences (Driver & Yeoh, 2000: 2) one that was refracted through various projects and sites of observation, examination, research, dissemination and display. In Impure and Worldly Geography, Bowd and Clayton explore Pierre Gourou's entanglement with tropicality and that of French geography more generally, carefully drawing out how it was 'a fluid and fractured site of difference' (p. 31), how it was imagined, experienced and embodied but also how it was negotiated and resisted. With an original emphasis on the significance of visuality in Gourou's work and understanding tropicality as a 'technology of seeing' (p. 90), they tease out the different 'technics of tropicality' (p. 87) that his work involved through his extensive use of cadastral maps, aerial photographs and census data, interviews and inventories, along with the different 'data deltas' (p. 108) that this subsequently spawned. They also productively illustrate how such technics captured and coded particular landscapes and their inhabitants or fostered fantasies of order, harmony and authenticity, laying the groundwork for wider regional and global/zonal fields of study and understanding in the process. They attend not just to how tropicality was envisioned and built with texts, images and spectacles but also how it was materialized by political economy and colonial violence and by particular forms of 'jungle capitalism', which yoked tropicality to capitalist and imperialist expansion. The book offers a fascinating insight into how Gourou's tropicality was 'scaled up' (p. 139) and subsequently became 'networked' as questions of imperial crisis, development and decolonization, along with practices of comparison and expertise, came more fully into view after World War Two. Working in and across various international fora, Gourou was drawn into and helped to fashion 'a bio-political framing of the tropics' (p. 141) in which bodies and populations became objects of analysis, targets of intervention and matters of security. The book begins by exploring how Indochina was identified, constructed and experienced as 'tropical' or was subject to French colonial