The theme of this collection is innovation in shipping and trade in widely ranging periods and settings. There are discussions of triremes, the introduction of steam-screw propulsion into the British mercantile marine and the Royal Navy in the 1840s, and the fortunes of P&O between 1914 and 1932. There are also studies of a Devon merchant's part in English commercial expansion in the early 17th century, and British trading along the coast of Southern Africa in the 19th century. The final essay takes a look at picture postcards as a source for maritime historical research.