Hip-hop soul is a subgenre of contemporary R&B music, most popular during the early and mid 1990s, which fuses R&B or soul singing with hip-hop musical production. The subgenre had evolved from a previous R&B subgenre, new jack swing, which had incorporated hip-hop influences into R&B music. By contrast, hip-hop soul is, as described in The Encyclopedia of African American Music, "quite literally soul singing over hip-hop grooves".