Echoes: The Best of Pink Floyd is the fourth compilation album by the English rock band Pink Floyd, released on 5 November 2001 by EMI internationally and a day later by Capitol Records in the United States. It debuted at #2 on the Billboard 200 album chart on 24 November 2001, with sales of 214,650 copies. It remained on the chart for 26 weeks. The album was certified Gold, Platinum and Double Platinum on 6 December 2001 in the US by the RIAA. It was certified Triple Platinum in the US on 8 January 2002, and Quadruple Platinum on 10 September 2007.

The album was initially planned to be more "energetic" than his previous work, but ended up presenting a wide range of styles such as R&B, pop, reggae, rock, disco, funk and soul music. Lyrically, Unorthodox Jukebox revolves around the theme of relationships, incorporating more explicit lyrics and subjects than his previous material. Critical response to Unorthodox Jukebox was generally favorable; many reviewers compared Mars's work to that of his previous album, while others deemed its lyrics shallow.