This is an exceptional book that explores the way steam power promoted a distinct type of globalisation. The book’s theme is really well chosen - Darwin avoids a traditional global history based upon big land empires and focuses on the marginal coastal ports and the way these trading zones, packed with foreign merchants and labour forces, connected the world, and exerting their own influence on the hinterland. The book is packed with information, but is always clearly written and the constantly shifting focus makes it a page-turner. It is full of constantly surprising and fascinating. I would give it 6-stars if I could.

After a couple of chapters surveying previous globalisations (ancient and post-Columbus systems) the book offers an explanation of how steam was able to make such dramatic changes so fast, first dismantling the existing world order and rapidly re-fashioning another Europe-dominated system (though Darwin notes how much of the trade, transport and specialist skills were carried out by non-Europeans).

Coal-powered steam ships circled the world, favouring deep sea harbours with good dock facilities. Even with these advantages docks needed a commercial hinterland to become really world class - steam-powered rail transport enabled local regions to export commodities that were needed to live (grain, cotton, spices) or to fuel further modernisation (tin, coal, rubber, oil). But the ports were always vulnerable to big geopolitical changes, such as wars, protectionist trade policies or new routes (there is lots about the changes the Suez Canal brought).

This is all fascinating stuff, but (for me) the real selling point is the case studies of the major ports in different parts of the world (New Orleans, Bombay, Singapore, Liverpool, Odessa, Montreal, Calcutta, and Smyrna - to name just some of the many covered). The level of detail was well-pitched and kept closely linked to the main theme, but they add up to make a mouth-watering whistle-stop tour of the Victorian world of a kind I had never really read before. I really enjoyed digging into what made them all different. The final sections on the decline of the steam era and the rise of intolerant and aggressive nationalism was also eye-opening. It has to be one of my favourite books of the year and I can wholeheartedly and enthusiastically recommend it.

After Tamerlane, John Darwin’s global history of empires was an invaluable resource when I studied imperialism and I can easily see his masterly new book, Unlocking the World becoming the same for anyone interested in nineteenth century imperialism. Darwin takes as his theme the part port cities played in globalisation, specifically focusing on the period between 1830 and 1930 when steam power dramatically accelerated the movement of goods, information, money, ideas and labour across the world.

Darwin shows that steam globalisation, precursor to our 21st century globalised world, wasn’t uniform and how it took different forms at different times and in different places. The port cities he uses in detail to illustrate his argument include: New Orleans, Montreal and New York in North America; Mumbai, Kolkata, Singapore, Hong Kong and Shanghai in Asia; Marseilles, London, Liverpool, Rotterdam and Hamburg in Europe. Many others, such as Montevideo, Smyrna and Trieste also feature. Looking at the list of busiest ports today, only the Southeast Asian ports still remain among the busiest 10 in the world with Rotterdam and Hamburg in the top 20. And while the world today is very different, Unlocking the World is still very relevant, “’Globalisation’ implies a free-trading, free-moving world in which economic efficiency is the key to wealth and power.” says Darwin, leading into a discussion of how steam globalisation was an age of coercion, racial exclusion, nationalism and gross inequality – ring any bells?

There is so much excellent material here, I particularly liked Darwin’s summary of the economic consequences of WW1 on France and Britain (rather than on Germany and being one of the causes of WW2) and how he brought to life the vibrant migrant merchant communities, for example Parsis in India and mainland Chinese in Singapore.

Unlocking the World is a fantastic book, one that I know I’ll certainly be getting a paper copy once published. Highly recommended for anyone interested in how we got to today’s messed up world.

I’m very grateful to Penguin, Allen Lane and Netgalley for the opportunity to read an advance copy of Unlocking the World.