Applauded as ‘a sweeping account of how the sea routes of Asia have transformed a vast expanse of the globe over the past five hundred years, powerfully shaping the modern world’, In Asian waters has been called ‘a tour de force’ (Cuauhtemoc Villamar: Journal of World History), ‘a powerful history of rupture and change’ (Yorim Spoelder: Asian Review of Books), ‘the best stock-taking that we have of the field’ (Fahad Ahmad Bishara: Journal of International Maritime History) and ‘a landmark … in maritime Asian scholarship’ (Stephen Morillo: Asian Review of World Histories). It is hyped as ‘a magnificent oceanic history of a continent’ (Sugata Bose), ‘an epic yet intimate history of Asia’s seas’ (Sunil Amrith), ‘a lively, kaleidoscopic introduction to a great arc of maritime history’ (Karen Wigen) and ‘a deeply sourced, eloquently executed, globe-spanning history … across the Indian Ocean, to the South China and Sulu seas and into the Pacific’ (Matt Matsuda). Per Francesca Trivellato, it ‘makes the case for maritime Asia as the birthplace of modernity and its discontents’, so much so that ‘this sweeping account will bury once and for all the Orientalist trope of Asia as a continent of agrarian empires’.

The book has six parts, sub-divided into 14 chapters. The parts are: (a) Maritime connections, (b) Bodies of water, (c) Religion on the tides, (d) Cities and the sea, (e) The bounty of the oceans, and (f) Technologies of the sea. With these large chunks of space, Tagliacozzo studies faith, urbanism, physical-environmental space, and maritime technologies, the last containing an engaging chapter on lighting the seas. But its large thematic canvas means that this cannot be a book based on primary sources. It is anyway challenging to write a history of the Indian Ocean (henceforth IO) world that contains several nations, languages, religions, cultural practices and a bewildering array of arcane and well-known scripts.

It is difficult to understand the book's appeal. It is too facile for the specialist reader, too sketchy to serve as a guide for instructors, and students will not benefit from Tagliacozzo's eclectic mixing of themes and temporal frames. The primary focus is Southeast Asia, there is little on South Asia, although the sub-continent's locational significance is acknowledged. I wanted more about the China seas in the eighteenth century (Asian port cities, 1600–1800: Local and foreign cultural interactions, ed. Haneda Masashi (Singapore: NUS Press, 2009); ‘Canton and Nagasaki compared’, Special Issue, ed. Haneda Masashi and Leonard Blussé, Itinerario 37, 3 (2013)) and more on British Calcutta and Rangoon in the long nineteenth century (Kaoru Sugihara, ‘The resurgence of Intra-Asian trade, 1800–1850’, in How India clothed the world: The world of south Asian textiles, 1500–1850, ed. Giorgio Riello and Tirthankar Roy (Leiden: Brill, 2009), pp. 139–169)). Many works are absent in the bibliography which is heavily tilted in favour of Anglophone scholars based in the West, Bahasa works excepted. As for the sub-title of the book, Yemen gets a yes, but I am not so sure about Yokohama which enters global history only in 1853–54 when Commodore Perry's fleet of warships arrived to ‘open up’ Japan.

I found Tagliacozzo's spatial frame puzzling. There is a continuing debate about the geographic and networked spaces of the IO since networks vary over time. The IO is already an incoherent unit, and when the Sulu and Japan seas move into it, the incoherence is exacerbated. In including the latter, Tagliacozzo exposes his book to divergent claims and contestations which Marcia Yonemoto’s and Peter Shapinsky’s works on Japanese cartographic practices reveal. Korea for example, rejects this name and calls it the East Sea instead.

In Tagliacozzo's study of 500 years, Asian waters underwent different experiences. At the start of the sixteenth century, Aden was Yemen's most important transit point; by the century’s end it had lost out to Mocha. Persian Gulf and Red Sea routes oscillated in importance. Ottoman Levantine transit trade via Hormuz flourished amongst tensions in the Red Sea. Between 1681 and 1694, Gulf shipping to Surat had 77 ships, exceeding that of the Red Sea (70 ships). Even as Bombay eclipsed Gujarat as a regional political and manufacturing centre by the mid-eighteenth century, Surat remained financially active, providing banking and credit facilities, while Gujarati cloth financed slave purchases. The Mozambique slave-trade became central in a trade against Indian cotton to Brazil and the Americas from the 1740s. A southwest IO trading bloc based on Cape Town emerged at that century’s end, again based on Indian cotton against slaves. Slave ships sailed around the Cape and across the Atlantic; the trade climaxed in 1789–90 when about 46 ships, carrying over 16,000 slaves, circumnavigated the Cape, bound for sugar and coffee plantations in St. Domingue. Omani resurgence saw it vying with the Portuguese and British empires for influence in the Gulf and the Arabian Sea. At its peak in the nineteenth century, Omani control extended across the Hormuz Strait to Iran and what became Pakistan, and as far south as Zanzibar. In the eastern seas, polities declined prior to European dominance: the Khmer Empire and Lanka from the fifteenth century, Ava and Majapahit Java in 1527, Bengal (1538), Pegu (1539), Lan Na (1558), Demak (1568), Cambodia (1594), and Ayutthaya (1596). The Sulu Sea responded to the world capitalist economy and the forward movement of colonialism through piracy and a slave raiding, which saw captives assimilated on a massive scale into traditional Sulu society. Eric Tagliacozzo could have emphasised more the variations in Asian seas instead of flattening them ‘from Yemen to Yokohama’.