"Enter Sandman" is a song by American heavy metal band Metallica, featured as the opening track and lead single from their eponymous 1991 album Metallica. The song was produced by Bob Rock, and the music was written by Kirk Hammett, Lars Ulrich, and James Hetfield. Vocalist and guitarist Hetfield wrote the lyrics, which deal with nightmares.The single achieved gold certification for more than 500,000 copies shipped in the United States, spurring sales of over 15 million copies for Metallica and propelling Metallica to worldwide popularity. Acclaimed by critics, the song is featured in all of Metallica's live albums and DVDs released after 1991 and has been played live at award ceremonies and benefit concerts. During some live performances, after James Hetfield sings "Exit light" he'll ask the crowd to sometimes either "Sing it" or "What is it?" which the crowd will answer in unison "Enter night". This is probably the song that most crowds can get into as is "Master of Puppets" where...