Black Sabbath is the eponymous debut album by English heavy metal band Black Sabbath. Released on 13 February 1970 in the United Kingdom, and later on 1 June 1970 in the United States, the album reached number eight on the UK Albums Chart and has been categorised as the first major album to be credited with the development of the heavy metal genre.According to guitarist Tony Iommi, the album was recorded in a single day on 16 October 1969, while other sources say that 17 November 1969 was the date of recording. Iommi said: "We just went in the studio and did it in a day, we played our live set and that was it. We actually thought a whole day was quite a long time, then off we went the next day to play for £20 in Switzerland." Aside from the bells, thunder, and rain sound effects added to the beginning of the album's opening track, there were virtually no overdubs added to the album. Iommi recalls recording live: "We thought 'We have two days to do it and one of the days is mixing.' So we played live. Ozzy was singing at the same time, we just put him in a separate booth and off we went. We never had a second run of most of the stuff."
According to Allmusic's Steve Huey, the album is "the birth of heavy metal as we now know it". Huey noted that the album "transcends its clear roots in blues-rock and psychedelia to become something more". The songs on the album's first half feature simple blues licks by Iommi and deal with themes characteristic of heavy metal, including evil, paganism, and the occult. Most of the second half has blues-rock jamming. Former Metal Maniacs magazine editor Jeff Wagner credited the album for making distinction between rock and roll and heavy metal. He said that the album transfigured blues rock into "something uglier, found deeper gravity via mournful singing and a sinister rhythmic pulse" Sputnikmusic's Mike Stagno observed that Black Sabbath combined elements of rock, jazz, and blues, with heavy distortion to create one of the most influential albums in metal history
Musically and lyrically the album was considered quite "dark" for the time. The first song on the album is based almost entirely on a tritone interval played at slow tempo on the electric guitar. The song's lyrics concern a "figure in black" which bass player Geezer Butler claims to have seen after waking up from a nightmare.
In 1989, Kerrang! listed the album at number 31 among the "100 Greatest Heavy Metal Albums of All Time". In 2000, Q magazine included Black Sabbath in their list of the "Best Metal Albums of All Time" and stated, "[This] was to prove so influential it remains a template for metal bands three decades on". In 2003, the album was ranked number 241 on Rolling Stone magazine's list of The 500 Greatest Albums of All Time; it was ranked number 243 in a revised edition of the list in 2012. In retrospect, the album has been lauded as perhaps the first true heavy metal album. Furthermore, it has been credited for being the first record in the stoner rock and goth genres.