Question: Which lead vocalist wrote songs for Black Sabbath?
Context: The Heaven & Hell Tour was the ninth world concert tour by Black Sabbath between April 1980 and February 1981 to promote their 1980 studio album, "Heaven and Hell."  The tour marked the band's first live shows with vocalist Ronnie James Dio, who replaced original vocalist Ozzy Osbourne the previous year; drummer Vinny Appice, who replaced original drummer Bill Ward in the middle of the tour's North American leg after Ward suddenly left the band due to personal issues; and keyboardist Geoff Nicholls, who played keyboards on the "Heaven and Hell" album and accompanied the band on this tour as a sideman.  For a portion of the North American tour, which was popularly known as the "Black and Blue Tour", Black Sabbath co-headlined with Blue Öyster Cult, with whom they shared a manager, Sandy Pearlman.  The arrangement reportedly set attendance records but caused friction between the two bands as well as between Black Sabbath and Pearlman. The Best of Black Sabbath is a double CD compilation album by Black Sabbath released in 2000 on the Sanctuary Records label.  Its 32 songs are presented chronologically from the band's first 11 albums, spanning the years 1970 to 1983.  Black Sabbath's classic six-album run, from 1970s debut "Black Sabbath" through 1975's "Sabotage" is celebrated with three to six songs from each album.  Original vocalist Ozzy Osbourne's subsequent final two albums with the band, 1976's "Technical Ecstasy" and 1978's "Never Say Die! ", are represented by one and two songs, respectively.  Replacement Ronnie James Dio's early 80's stint fronting the band on two albums is acknowledged with the title track of 1980's "Heaven and Hell" and a track from 1981's "The Mob Rules".  The compilation closes with a song from 1983's attempted rebirth, "Born Again", former Deep Purple vocalist Ian Gillan's sole album with the band.  "The Best of Black Sabbath" does not include any later material with vocalists Glenn Hughes (1986's "Seventh Star"), Tony Martin (1986–96) or the returning Dio (1992's "Dehumanizer"). The Collection is a compilation album released by English heavy metal band Black Sabbath in 1992.  The album was released on the label Castle, who released two CD versions of this album in the UK, both with the same cover art and songs.  The album includes greatest songs of Black Sabbath with Ozzy Osbourne prior to his dismissal in 1979, from the eponymous album to "Never Say Die! ".  The album has 15 tracks, two from "Black Sabbath", two from "Paranoid", one from "Master of Reality", two from "Black Sabbath Vol.  4", two from "Sabbath Bloody Sabbath", two from "Sabotage", two from "Technical Ecstasy" and two from "Never Say Die! ". The Eternal Idol is the thirteenth studio album by English rock band Black Sabbath, released on November 23, 1987.  It is the first Black Sabbath album to feature vocalist Tony Martin.  It spent six weeks on the "Billboard" 200 chart, peaking at 168.  It was also the last full album of new material by Black Sabbath to be released by Warner Bros.  Records (in North America), and the final album through their original label Vertigo Records until the release of "13" in 2013. John Michael "Ozzy" Osbourne (born 3 December 1948) is an English singer, songwriter, and actor.  He rose to prominence in the early 1970s as the lead vocalist of the heavy metal band Black Sabbath.  He was fired from Black Sabbath in 1979 and went on to have a successful solo career, releasing 11 studio albums, the first seven of which were all awarded multi-platinum certifications in the US.  Osbourne has since reunited with Black Sabbath on several occasions, recording the album "13" in 2013.  His longevity and success have earned him the informal title of "Godfather of Heavy Metal". Tommy Clufetos (born December 30, 1979) is an American session drummer most noted for his work with Black Sabbath during their Black Sabbath Reunion Tour, which highlighted their new album "13".  He also toured with them on their final tour.  He's also the drummer for Black Sabbath vocalist Ozzy Osbourne. "The Mob Rules" is a song by British rock band Black Sabbath from their 1981 album, "Mob Rules".  The song was written by Ronnie James Dio and Tony Iommi.  The song also released as the first single from the album. Godspeed is an American metal band formed in 1992.  Following the release of their debut album Ride on Atlantic Records, produced by Rachel Bolan of Skid Row, the band embarked on two high-profile tours as the opening act for Black Sabbath and Dio.  Godspeed gained attention with an appearance on the 1994 Black Sabbath tribute album "Nativity in Black", on which they teamed up with guest vocalist Bruce Dickinson of Iron Maiden to record a cover of the Black Sabbath song, "Sabbath Bloody Sabbath." Mob Rules is the tenth studio album by English rock band Black Sabbath, released in November 1981.  It followed 1980's "Heaven and Hell", and it was the second and last Black Sabbath studio album to feature lead vocalist Ronnie James Dio prior to the 1992 album "Dehumanizer". The Black Sabbath Story Vol.  2 - 1978-1992 is a documentary video about the biography of the heavy metal band Black Sabbath.  It is the follow-up to "The Black Sabbath Story Vol.  1 - 1970-1978", and it's about their story from the leaving of Ozzy Osbourne to the recording of Dehumanizer, discussing the line-up changes Black Sabbath experienced during the period between 1978 and 1992.  In addition to comments by the storic members Geezer Butler and Tony Iommi, there are interviews with other people that have been in the band, like Ronnie James Dio, Ian Gillan, Cozy Powell and Vinny Appice.  There are also live clips and video clips of various songs.  In 2002 a DVD Version has been released, with 19 min of never-seen footage, not included in the previous VHS Version.
Answer: Ronnie James Dio