In her consistently enlightening new book, Captives: Britain, Empire, and the World, 1600-1850, award-winning historian Linda Colley examines the limitations and vulnerabilities of the British Empire during its most wide-ranging period. In 1820, one out of every five human beings on earth was under English rule a formidable fact to consider. Yet Colley proposes that because of its small size, and its dependence on maritime power and the land and resources of other people, "Britain's empire was always overstretched, often superficial, and likely to be limited in duration."In Colley's view, unless we understand the phenomenon of the captivity of British subjects by enemies of that imperial power, we cannot properly appreciate or assess Britain's overseas experience. By focusing on captivity narratives from the early 17th century to the Victorian era, Colley demonstrates the weaknesses of British power during that period. Focusing on narratives from the Mediterranean (primarily North Africa), North America and India, with a short section on Afghanistan, she offers the stories of men and women of diverse ethnic backgrounds as a means of increasing our understanding of the captivity experience. Her book offers an illuminating re-examination of the colonial experience, the repercussions of which are still being felt today. Almost without exception, Colley demonstrates, individuals became captives because they were not part of the aristocracy, and the government was powerless or indifferent when it came to offering help. It's interesting to note that when paying ransom to obtain a captive's release was an option, the government did not play a primary role, but churches in England often did. Colley's discussions of each of the narratives is engrossing. We see how individuals learned to adapt to changing circumstances, often with the objective of personal survival. Although the narratives often mix insightful reportage with religious, political and historical prejudice, they remain valuable testaments to the relationship between the oppressor and oppressed, despite their shortcomings as historical truth. This is an insightful and stimulating book that presents history with a fresh perspective. Roger Bishop is a frequent contributor to BookPage.