The logbook became the formal document recording the progress and management of a ship. The name is derived from the 'log', an instrument used to estimate the speed of the ship. It was principally a navigational account in which the speed, course and location of the vessel were carefully recorded on a daily, often hourly basis. It also came to include a written account of the important aspects of life on board; victualling, health and punishments were all recorded. A note was also kept of the weather, the wind force and direction. Keeping a logbook became so commonplace that dockside printers would sell prepared pages for officers to use on board.

Over the years, such documents came to assume wider significance. For example, their submission to the authorities was used to secure payment for the recording officer. They were the formal record of a ship's management in the unfortunate event of a court-martial. Even today, they are important documents for insurance purposes.

Given this importance, it is not surprising that many logbooks have survived over the centuries. Great Britain is particularly fortunate in this respect, and thousands of logbooks, many from as early as the late 17th century and many more from the 'golden age of sail' of the 18th and early 19th centuries can be found in the National Archives, the Caird Library of the National Maritime Museum, and the British Library.