Bee Gees are a musical group that was originally made up of three brothers: Barry, Robin, and MauriceGibb. The trio were successful for most of their forty plus years of recording music, but they had two distinct periods of exceptional success: as a harmonic "soft rock" act in the late 1960s and early 1970s, and as a foremost act of the disco music era in the late 1970s. The group sang three-part tight harmonies that were instantly recognisable; Robin's clear vibrato lead was a hallmark of their earlier hits, while Barry's R&B falsetto became their signature sound during the late 1970s and 1980s. The brothers co-wrote all of their own hits, as well as writing and producing several major hits for other artists. They have had at least one top-ten U.S. hit in each of five decades: "I've Gotta Get a Message to You", "I Started a Joke" (1960s); "Nights on Broadway", "How Deep Is Your Love", "Stayin' Alive" (1970s); "One" (1980s); "Alone" (1990s); and "This Is Where I Came In" (2000s).