Roger Keith "Syd" Barrett (6 January 1946 - 7 July 2006) was an English singer, songwriter, musician, composer, and painter. Best known as a founder member of the band Pink Floyd, Barrett was the lead singer, guitarist and principal songwriter in its early years and is credited with naming the band. Barrett was excluded from Pink Floyd in April 1968 after David Gilmour took over as their new guitarist, and was briefly hospitalised amid speculation of mental illness. Barrett was musically active for less than ten years.
London Underground, Blackhill Enterprises and gigs
While Pink Floyd began by playing cover versions of American R&B songs, by 1966 they had carved out their own style of improvised rock and roll, which drew as much from improvised jazz. After Bob Klose departed from the band, the band's direction changed. However, the change was not instantaneous, with more improvising on the guitars and keyboards. Mason reflected, "It always felt to me that most of the ideas were emanating from Syd at the time."  At this time, Barrett's reading reputedly included: Grimm's Fairy Tales, Tolkien's The Hobbit and Lord of the Rings, Carlos Castaneda's The Teachings of Don Juan, and The I-Ching. During this period, Barrett wrote most of the songs for Pink Floyd's first album, and also songs that would later appear on his solo albums. In 1966, a new rock concert venue, the UFO (pronounced as "you-foe"), opened in London and quickly became a haven for British psychedelic music. Pink Floyd, the house band, was its most popular attraction and after making appearances at the rival Roundhouse, became the most popular musical group of the "London Underground" psychedelic music scene.  By the end of 1966, Pink Floyd had gained a reliable management team in Andrew King and Peter Jenner. Towards the end of October 1966, Pink Floyd, with King and Jenner, set up Blackhill Enterprises, to manage the group's finances. Blackhill was staffed by lodgers Jenner found in his Edbrooke Road house, and among others, Barrett's flatmate, Peter Wynne Wilson (who became road manager, however, since he had more experience in lighting, he was also lighting assistant). King and Jenner wanted to prepare some demo recordings for a possible record deal, so at the end of October, they booked a session at Thompson Private Recording Studio, in Hemel Hempstead. King said of the demos: "That was the first time I realised they were going to write all their own material, Syd just turned into a songwriter, it seemed like overnight."  King and Jenner befriended American expatriate Joe Boyd, the promoter of the UFO Club, who was making a name for himself as one of the more important entrepreneurs on the British music scene. The newly hired booking agent, Bryan Morrison, and Boyd had proposed sending in better quality recordings. From Morrison's agency the band played a gig outside London for the first time. In November, the band performed the first (of many) strangely named concerts: Philadelic Music for Simian Hominids, a multimedia event arranged by the group's former landlord, Mike Leonard, at Hornsey College of Art. They performed at the Free School for the following two weeks, before performing at the Psychodelphia Versus Ian Smith event at the Roundhouse in December, arranged by the Majority Rule for Rhodesia Campaign, and an Oxfam benefit at the Albert Hall (the band's biggest venue up to this point).

Q: What did he do in London Underground?
A: became the most popular musical group of the "London Underground" psychedelic music scene.

Q: How did they become the most popular musical group?
A: In 1966, a new rock concert venue, the UFO (pronounced as "you-foe"), opened in London and quickly became a haven for British psychedelic music.

Q: What did they have to do with Syd Barrett?
A: Pink Floyd, the house band, was its most popular attraction and

Q: Did Barrett create any  more albums?
A: and after making appearances at the rival Roundhouse, became the most popular musical group of the "London Underground" psychedelic music scene.
Did it reach bill board charts?
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