Ska is a music genre that originated in Jamaica in the late 1950s and was the precursor to rocksteady and reggae. It combines elements of Caribbean mento and calypso with American jazz and rhythm and blues. Ska music is characterized by its fast-paced, dance style, and is almost exclusively written in a 4/4 time signature. The genre is known for its distinctive instrumentation, which includes a strong horn section, bass, guitar, drums, keyboard, and vocals.

Music historians typically divide the history of ska into three periods: the original Jamaican scene of the 1960s; the 2 Tone ska revival of the late 1970s in Britain, which fused Jamaican ska rhythms and melodies with the faster tempos and harder edge of punk rock forming ska-punk; and third wave ska, which involved bands from a wide range of countries around the world, in the late 1980s and 1990s.

Ska music has been influenced by and has influenced many other genres, including reggae, punk rock, and hip hop. The genre has also been used to address social and political issues, such as race, marijuana, and war.

In summary, ska is a music genre that originated in Jamaica in the late 1950s, characterized by its fast-paced, dance style, and distinctive instrumentation. It has a rich history and has influenced and been influenced by many other genres.