Tool is an American rock band from Los Angeles, California. Formed in 1990, the group's line-up has included drummer Danny Carey, guitarist Adam Jones, and vocalist Maynard James Keenan. Since 1995, Justin Chancellor has been the band's bassist, replacing their original bassist Paul D'Amour. Tool has won three Grammy Awards, performed worldwide tours, and produced albums topping the charts in several countries. The band emerged with a heavy metal sound on their first studio album Undertow in 1993, and later became a dominant act in the alternative metal movement with the release of their second effort, Ænima, in 1996. Their efforts to unify musical experimentation, visual arts, and a message of personal evolution continued with Lateralus (2001) and the most recent album 10,000 Days (2006), gaining the band critical acclaim and commercial success around the world.

Due to Tool's incorporation of visual arts and relatively long and complex releases, the band is generally described as a style-transcending act and part of progressive rock and art rock. The relationship between the band and today's music industry is ambivalent, at times marked by censorship and the band members' insistence on privacy.

Daniel Edwin "Danny" Carey (born May 10, 1961 in Lawrence, Kansas) is an American drummer best known for his work in American Grammy Award-winning progressive metal band Tool. He has also contributed to albums by artists such as ZAUM, Green Jellÿ, Pigface, Skinny Puppy, Adrian Belew of King Crimson, Carole King, Collide, The Wild Blue Yonder, Lusk, and the Melvins.

Carey's first encounter with the drums began at the age of ten by joining the school band and taking private lessons on the snare drum. Two years later, Carey began to practice on a drum set. In his senior year of high school in Paola, Kansas, Carey joined the high school jazz band and began to study under drumming great Ben Kelso specifically for jazz drumming training. Jazz would later play a huge role in his signature approach to the drum set in a rock setting. As Carey progressed through high school and later college at the University of Missouri–Kansas City, he began expanding his studies in percussion with theory into the principles of geometry, science, and metaphysics as well as delving into Sacred Geometry and certain hidden aspects of life and the occult. Carey also played jazz while attending college and got to experience the jazz scene in Kansas City.

William Darrell "Billy" Mays, Jr. (July 20, 1958 – June 28, 2009) was an American television direct-response advertisement salesperson most notable for promoting OxiClean, Orange Glo, and other cleaning, home-based, and maintenance products on the Home Shopping Network, and through his company, Mays Promotions, Inc. He and his business partner, Anthony Sullivan, were also featured on PitchMen, a TV series that documented their work. His distinctive beard and impassioned sales pitches made him a recognized television presence in the United States and Canada. Mays was found unresponsive by his wife in his Tampa, Florida, home on the morning of June 28, 2009. He was pronounced dead at 7:45 am, appearing to have died sometime overnight.

Mays was born in McKees Rocks, Pennsylvania, attended Sto-Rox High School, and was raised in Pittsburgh, Pennsylvania. He later attended West Virginia University, where he was a walk-on linebacker on its football team during his two years there. After dropping out, he worked for his father's hazardous waste company before moving to Atlantic City, New Jersey in 1983.