Rap is a musical style consisting of rhythmic and rhyming lyrics spoken or chanted over a beat. It differs from spoken word poetry through its use of an external musical meter or beat. Eminem is considered one of the greatest and most influential rappers of all time, known for his technical skill, emotionally and intellectually deep lyrics. As the best-selling artist of the 2000s in the US, some of Eminem's most successful albums include Recovery, Relapse, Encore, The Marshall Mathers LP 2, and Southpaw.