For those who are unfamiliar with the man's phenomenal career, Ronnie James Dio fronted no less than three classic metal bands. First there was Rainbow, the band Ritchie Blackmore formed after leaving Deep Purple, in which RJD appeared on the band's first three albums: 1975′s Ritchie Blackmore's Rainbow, 1976′s Rising and 1978′s Long Live Rock 'n' Roll. After that, he had the confidence and chops to replace the irreplaceable, taking over for Ozzy Osborne after he left Black Sabbath. With 1980′s Heaven and Hell and 1981′s Mob Rules, he gave that band one of the great second acts in rock and roll history before forming moving on to for his own band, Dio.

Longtime fan Corey Taylor told Radio.com that "It didn't matter what band he was with, the power of what he did just translated over any type of music." Case in point, Rainbow sounds very different from Sabbath and Sabbath sounds very different from Dio. "He could pick up on any type of music and make it his own," Taylor said. "He was wonderful. He's one of the best metal singers of all time� it's hard to sing his songs!"

Looking to show he was also up for the challenge, Taylor took on one of Dio's hardest, and most iconic songs, "Rainbow In The Dark." "That's been my favorite Dio song since I was very young," Taylor said. "I remember being so taken by the video and the song itself. it was so damn catchy. And it's just been one of those songs that has stuck with me through the years."

Taylor added, "A lot of people gravitate towards [Black Sabbath's] 'Heaven and Hell,' and 'Mob Rules,' or of course [Dio's] 'Holy Diver,' that's probably the one that people instantly recognize. But 'Rainbow in the Dark,' I was lucky that it wasn't already taken, but I called dibs pretty much immediately. 'That's mine!' I just tried to make it my own and do it in the spirit of the song. It is such a brilliant song."

Scott Ian, whose band covered Sabbath's "Neon Knights," also felt a connection to Dio, but it wasn't just his metal catalogue. "I heard him on the first Rainbow record. Years later, I heard some old 45′s of him singing doo-wop," he explained. "And that was great too!" He's not kidding. While Dio is an icon of heavy metal, he started his music career singing in doo-wop acts including Ronnie and the Red Caps and Ronnie Dio and the Prophets, before moving to heavy rock with a band called Elf, and then after that, Rainbow. "Pretty much everything he's done, especially his work with Sabbath, was a huge influence on Anthrax, and certainly on [Anthrax singer] Joey [Belladonna]," Ian said. "Joey is a massive Ronnie fan."

While Ian was 19 and Taylor was just nine years old when Dio's 1983 debut, Holy Diver came out, Lzzy Hale of Halestorm wasn't even born yet. (She was born in 1984.) Luckily, Hale had parents who liked to rock and turned her on to Dio at a young age. "Holy Diver was actually the first album that I heard from Dio, thanks to my very cool parents," she said. "When I got interested in singing and being in a band, they were like, 'Here, get into some real music.' It was Dio and Black Sabbath and Deep Purple and all the '70s hard rock and metal stuff." Her band ended up covering "Straight Through The Heart," off Dio's debut, which Hale says has been a part of her life for "a long, long time."

Tribute albums with A-list lineups are always difficult to put together, and RJD's wife/manager Wendy Dio, who produced this compilation, told Radio.com that it has been in the works for two and a half years. It was a long haul, due mostly to hectic schedules by the artists, but everyone was eager to pay tribute and give back, since the album will raise funds for the Ronnie James Dio Stand Up and Shout Cancer Fund. RJD succumbed to stomach cancer in 2010.