This book describes the expedition undertook by James Colnett (c. 1752-1806) with the ship HMS Rattler between 1793 and 1794 to survey adequate anchorage points in the Pacific Ocean for British merchant vessels.

Colnett had served as midshipman aboard HMS Resolution under Captain James Cook during his second Pacific voyage (1772-75), and had gained excellent knowledge of the ocean in the subsequent years, through his involvement with the trade in sea otter pelts, gathered on the north-west coast of North America and sold for a profit in China. Once Chinese ports closed to European fur traders, Colnett was nominated by the Admiralty to survey suitable harbouring places for British whalers.

Whale oil, particularly that of the sperm whale, was a highly useful commodity in the early modern period. It was used as lubrication for watches and other small machinery; protected metals from rust; and, most importantly, was excellent for oil lamps, as it burned brightly and did not give off any odour. A plate included in this book describes in great detail how sperm whales were hunted and how the valuable commodity was extracted.

Colnett's mapping of suitable anchorages was influential in opening up the Pacific Ocean to commercial whaling. By 1809, there were 72 British whalers in the region as well as vessels from other European nations. Later in the nineteenth century, overfishing and new technological advances, such as the discovery of paraffin in the 1830s, made sperm whale fisheries unprofitable, though intensive commercial whaling of other species did continue through to the mid-1980s when a moratorium suspended all commercial whaling from 1986.