A log book is a systematic daily or hourly record of activities, events and occurrences. Log books are often used in the workplace, especially by truck drivers and pilots, to log hours and distances covered.
Originally, log books were created for the purpose of ships to record the distances they covered. Since then, most ships have started using computerized systems and no longer use a formal log book for that purpose. Instead, log books are used to keep a record of events and to help navigate in the event that the radio, radar or GPS fail.
Log books are also used, often in an electronic format, by nuclear power plants and other energy producers. Log books also play a critical role in the manufacturing business. Their main use is for tracking and evaluating the manufacturing process.
A pilot's log book is used as a record of time and training to be used toward future certificates and ratings. It is also used as currency to comply with various regulations. Similarly, truck drivers use log books to ensure that they are keeping up with various transportation laws. Truck drivers are required to keep a detailed 24-hour log of their location and time spent off and on duty because they are only allowed to drive for a certain number of consecutive hours.