What is a concept album?

A concept album is a type of album characterized by its thematic or narrative consistency across all its tracks. Trent Reznor discusses his experience creating a concept album, explaining that it involved planning a comprehensive and coherent thematic and musical trajectory for the album. The album was designed to tell a story or explore a particular theme in detail, involving the creation of songs that follow an elaborate plan regarding the themes and musical style to be incorporated 1.