A bullet journal is a customizable organizational system that combines elements of a planner, diary, and to-do list. It uses bullet points and symbols to help users track tasks, events, and notes in a structured way. This method allows for flexibility, as individuals can design their layouts and sections according to their personal needs. The concept was created by Ryder Carroll, a designer who aimed to simplify the process of journaling and planning. Bullet journals can include monthly calendars, daily logs, habit trackers, and goal-setting pages, making them a versatile tool for managing time and enhancing productivity.