Ship's Log

The Ship's Log, known in jargon as the captain's log, was a form of log entry record-keeping that was used in human maritime tradition.

The log was used to inform the captain's superiors of what was happening on a mission and to record historical facts for future generations.

Popularization
The concept of captain's log was popularized by star trek, creating misconseptions about the log, the most popuar are the use of vioce as opposed to text, and the stardates.