Public Image Ltd (abbreviated as PiL) are an English post-punk band formed by singer John Lydon (a.k.a. Johnny Rotten), guitarist Keith Levene, bassist Jah Wobble, and drummer Jim Walker. The group's personnel has changed frequently over the years; Lydon has been the sole constant member. 　　Following the breakup of the Sex Pistols, Lydon was eager to pursue a more experimental project and formed PiL in 1978. Later that year, the group released its debut First Issue (1978), featuring an abrasive, bass-heavy sound and drawing on elements of dub, noise, and progressive rock.Their second album Metal Box (1979) pushed their sound further into the avant-garde, and is often regarded as among the most influential and challenging albums of the post-punk era. 　　By 1984, both Levene and Wobble had departed, and the group came under the direction of Lydon, who released a number of subsequent albums, including This Is What You Want... This Is What You Get (1984).After a late 1990s hiatus, Lydon reformed the group and has released several further albums, most recently What the World Needs Now... (2015).