Heavy metal music styles in its early years, but by 1969 vocalist Ian Gillan and guitarist Ritchie Blackmore had led the band toward the developing heavy metal style. In 1970, Black Sabbath and Deep Purple scored major UK chart hits with "Paranoid" and "Black Night", respectively. That same year, two other British bands released debut albums in a heavy metal mode: Uriah Heep with "...Very 'Eavy ...Very 'Umble" and UFO with "UFO 1". Bloodrock released their self-titled debut album, containing a collection of heavy guitar riffs, gruff style vocals and sadistic and macabre lyrics. The influential Budgie brought the new metal sound into
Heavy metal lyrics freedom of speech argument. Heavy metal has been the subject of critiques from "music industry watchdogs and parents’ groups for its violent, drug-related, sexual, antisocial and occult lyrics". During the 1980s, the PMRC, an advocacy group which was against the alleged presence of negative themes in popular music, used music professor Joe Stuessy to testify against metal. Professor Stuessy alleged that heavy metal songs focus on violence, substance abuse, perversion, S&M, and Satanism. Walser analyzed 88 metal songs' themes to determine if Professor Stuessy’s claims were valid. Walser found that the themes Stuessy claimed were common in metal were actually