The organizational logic of SecondHandSongs is both elegant and functional. The database operates with two core identifiers: a for each song composition, and a performance ID for each specific recording of that work. A "work" is defined as an equivalence class—a collection of performances that represent the same underlying song. For example, every version of a composition has a single common work ID.

Have you ever heard a song and felt a sudden wave of familiarity, only to realize it was originally recorded decades ago by a completely different artist? Tracking the complex lineage of music—from the original writer to the dozens of musicians who put their own spin on it—can be a daunting task. Enter , the premier crowdsourced database dedicated entirely to documenting cover versions, samples, and music adaptations. What is SecondHandSongs?

This is the most powerful view on the site. It lists the lifecycle of a song.