Metallica has become one of the most influential heavy metal bands of all time, and is credited as one of the "big four" of thrash metal, along with Slayer, Anthrax, and Megadeth. The band has sold more than 125 million records worldwide, including an RIAA-certified 66 million and Nielsen SoundScan-reported 58,000,000 in the US, making Metallica one of the most commercially successful bands of all time. The writers of "The Rolling Stone Encyclopedia of Rock & Roll" said Metallica gave heavy metal "a much-needed charge". Stephen Thomas Erlewine and Greg Prato of Allmusic said Metallica "expanded the limits of thrash, using speed and volume not for their own sake, but to enhance their intricately structured compositions", and called the band "easily the best, most influential heavy metal band of the '80s, responsible for bringing the music back to Earth".