A logbook (or log book) is a record used to record states, events, or conditions applicable to complex machines or the personnel who operate them. Logbooks are commonly associated with the operation of aircraft, nuclear plants, particle accelerators, and ships (among other applications). The term logbook originated with the ship's log—a maritime record of important events in the management, operation, and navigation of a ship. Originally, the term "Log Book" came about in early maritime navigation. The Captain was responsible for keeping a 'Log', as a minimum, of navigational wind, speed, direction and position. The speed was determined by ejecting a 'log' from the bow of the boat and measuring the time it took to reach the stern, thereby determining the speed. Format Logbooks come in many varieties, but they are sometimes standardized in form and/or content within certain organizations or industries. In some applications like flight training or trucking hours of service, they contain specific information used to satisfy legal requirements. Electronic logbooks Prior to the advent of mobile computing, logbooks were almost exclusively printed and bound in hard copy form. While physical logbooks offer advantages in frontline applications with many users (like aircraft maintenance logs), the proliferation of cloud computing and mobile devices has enabled the development of electronic logbooks. They may be as complex as software packages, or as simple as editable spreadsheets, but electronic logbooks offer several advantages—like virtually unlimited capacity and digital backups. Applications Maritime logbooks To record key navigation, engine watch, port calls and other operational activities on board vessels of all sizes, marine logbooks must meet the specific reporting requirements of IMO, SOLAS and flag states. When maritime logbooks are of the electronic variety, manually-inserted information is normally combined with data recorded from the vessel's instruments such as time and position. Typical marine logbooks are: Deck logbook – Records navigational events related to the voyage and operations on board Dynamic positioning logbook – Manual recording of operations related to Dynamic Positioning (DP) operations Engine logbook – Records engine events related to the engine and machinery operation Oil record book – Records events related to oil and dirty water as required by IMO's MARPOL convention Operational log – Records events related to vessel operation, i.e. performance, cargo handling and maritime operations. The Operational Log will typically need some customisation to owner's requirement and trade. Radio logbook – Records events relevant to radio traffic as