A Perfect Circle is an American rock supergroup formed in 1999 in Los Angeles by guitarist Billy Howerdel and vocalist Maynard James Keenan of Tool. Known for their dark, melodic sound, the band has released four studio albums: Mer de Noms, Thirteenth Step, Emotive, and Eat the Elephant. After its early 2000s success, the group experienced several hiatuses due to Keenan's commitments with other projects, leading to a rotating lineup of talented musicians. Despite these changes, Howerdel and Keenan have remained the creative core, with Howerdel composing music and Keenan writing lyrics and melodies. The band is recognized for their critically and commercially successful albums and dynamic live performances, maintaining a dedicated following with both original material and inventive reinterpretations of other artists’ songs.