Focus began as a trio formed by Thijs van Leer, a singer, flautist and keyboard player who had studied classical music at the Dutch Conservatorium.
His partners in Focus were bassist Martijn Dresden and drummer Hans Cleuver.
Prior to taking on the name Focus, the group worked as a support band in one of the myriad European productions of Hair.
Their first album was In And Out Of Focus, by which time guitarist Jan Akkerman had joined from another Dutch group, Brainbow.
Nobody really paid much attention when producer Mike Vernon signed Focus in late 1970. After all, Europeans couldn't rock.
It turned out that Focus could rock harder than almost anyone in sight. Hocus Pocus (1973) was the song that proved it.
Featuring the curious yodelling of van Leer, it was amongst the most distinctive records ever made, tracing the connection that nobody knew existed between uncompromising prog rock and novelty pop.
Jan Akkerman's original vision for Hocus Pocus called for bagpipes to duel with his stampeding guitar before it was decided that yodeling would be even stranger. The single entered the Billboard Top 40 on 21 April 1973, and would go Top 10.
Their biggest hit, Sylvia, made the US Top 100 and peaked at #4 in the UK earlier in 1973. The band toured the UK (21 concerts to packed houses in 23 days) and the States, and before the end of 1973, they were wallowing in gold discs.
They had a run of problems over their bass player position before Bert Ruiter joined on a reasonably firm basis, and English drummer Colin Allen replaced Pierre van der Linden - calling on experience he had gained with John Mayall, Zoot Money, and Stone The Crows. Allen left again, however, in 1975.
Two Focus albums also hit the UK Top 10.
Thijs van Leer
Organ, flute, vocals
Pierre van der Linden