It is a music book. A timeline is a way of displaying a list of events in chronological order, sometimes described as a project artifact. It is typically a graphic design showing a long bar labelled with dates alongside itself and usually events labelled on points where they would have happened. Timelines are often used in education to help students and researchers with understanding the order or chronology of historical events and trends for a subject. When showing time on a specific scale on an axis, a timeline can be used to visualize time lapses between events, durations (such as a lifetimes or wars), and the simultaneity or overlap of spans and events.