The era also provided some of the greatest advances in rapping technique. Kool G Rap, referring to the golden age in the book "How to Rap" said, "that era bred rappers like a Big Daddy Kane, a KRS-One, a Rakim, a Chuck D... their rapping capability and ability – these dudes were phenomenal". Many of hip hop's biggest artists were also at their creative peak. Allmusic said the golden age "witnessed the best recordings from some of the biggest rappers in the genre's history... overwhelmingly based in New York City, golden age rap is characterized by skeletal beats, samples cribbed from hard rock or soul tracks, and tough dis raps... rhymers like PE's Chuck D, Big Daddy Kane, KRS-One, Rakim, and LL Cool J basically invented the complex wordplay and lyrical kung-fu of later hip-hop".