Focus is a Dutch progressive rock band formed in Amsterdam in 1969 by keyboardist, vocalist, and flautist Thijs van Leer, drummer Hans Cleuver, bassist Martijn Dresden, and guitarist Jan Akkerman.

After recording two albums with various musicians, including guitarist Phillip Catherine, singer P. J. Proby, and drummers Colin Allen, David Kemper, and Steve Smith, Focus dissolved in 1978.

Focus formed in mid-1969 by keyboardist, vocalist, and flautist Thijs van Leer, who recruited bass guitarist Martijn Dresden and drummer Hans Cleuver[2] after he met them at sessions for the Jazz and Poetry radio program in Hilversum, Netherlands.

[7] In their search for more work and a steady income, Focus was chosen to play as part of the pit band for the Dutch production of the rock musical Hair produced by Welsh actor Victor Spinetti.

[12] In 1970, Focus reached contact with Hubert Terheggen, director of Radio-Tele-Music Belgium-Holland, a music publishing division of Radio Luxembourg, through connections with Dresden's father.

[11][4] Focus proceeded to retaliate with van Leer playing the flute to the audience as a distraction while the rest of the group trashed the dressing room, after which they were arrested and spent a night in jail.

The album saw an American release in October by Sire Records, who had secured the rights to the band's international distribution, with "House of the King" added to the track listing.

[19] Late in 1970, Akkerman had become increasingly unhappy with Cleuver and Dresden as a rhythm section and missed his former Brainbox bandmate, drummer Pierre van der Linden.

[22][23] Following rehearsals at Groeneveld Castle in Baarn, the band recorded Focus II, better known by its international title Moving Waves, in April and May 1971 at Sound Techniques and Morgan Studios, London.

Akkerman changed his sound, moving from a Gretsch White Falcon to a 1957 Gibson Les Paul Custom which enabled him to "'sing' on the guitar" to compensate for the group's weak vocals.

[12] Focus found their new bassist in Bert Ruiter, who had previously rehearsed with van der Linden prior to a gig in Texel in June 1971,[31] and went on to see the band live around ten times thereafter.

[4] On 28 May 1972, Focus were booked to play the Lincoln Festival for an estimated 40,000 people, but the band arrived too late for their spot and were unable to reschedule, leaving them furious at the missed opportunity.

Two days later, Focus made their British television debut with a pre-recorded performance of excerpts of "Eruption" and "Hocus Pocus" on the BBC music show The Old Grey Whistle Test.

[37] To support the album, Focus began their largest tour since their formation with spots at the Reading Festival on 12 August 1972 followed by the Melody Maker Poll Awards show at The Oval, London on 30 September.

Akkerman had expressed a wish to put down "great ideas" he had written over the past year, but extensive touring had left the band physically and mentally exhausted which reduced their eagerness to write and record new group material.

[48] It closes with a six-part, 20-minute conceptual title track inspired by Akkerman once eating a hamburger while watching cartoons at his hotel room in New York City and was put down in basic form during the 1973 Chipping Norton sessions.

[51] Focus toured Hamburger Concerto from March 1974, starting with dates across Europe, including two in London that were filmed for broadcast on the BBC2 and US television music series In Concert.

[54] They were featured on the nationally syndicated Don Kirshner's Rock Concert show aired live from Long Beach, California, giving the band widespread exposure.

To solve the issue, he and van Leer returned to Morgan Studios and put down "Red Sky at Night" and "Avondrood", the latter featuring the two singing in Dutch.

[62] After Kemper left when recording was complete, Akkerman wished van der Linden to return, thinking he was responsible "for at least 40%" of the band's success and said he "wouldn't leave Focus" with him on the drums.

[65] With van der Linden gone, Focus cancelled a proposed 34-date UK tour and brought back Kemper during subsequent rehearsals after a desperate plea from de Jong.

After van Leer signed a deal with EMI in April 1976 to record a new Focus album, work did not begin until late 1977 when the band faced potential legal action if they did not release something.

[67] Recording took place in December 1977 at EMI Studios in Haarlem, Amsterdam with van Leer, Ruiter, Albers, and a returning Catherine, who was contractually required to perform.

[67][69] In the search for a suitable lead vocalist de Jong, a friend of American singer P. J. Proby, rang his Netherlands-based manager and invited him to the studio, thinking his vocals would replace Akkerman's lyrical playing.

[72] After this initial collaboration, an executive at Phonogram Records suggested the pair work on an album of re-recorded Focus songs with English producer Trevor Horn, but it fell through.

Engineer Theo Balijon claimed Jacobs cut corners and pushed for the strongest tracks to be completed quickly to save production costs, which "unintentionally increased the animosity between Jan and Thijs".

In 1997, van Leer reformed Focus with Cleuver and Ruiter returning on drums and bass, respectively, and 21-year-old Dutch guitarist Menno Gootjes who was studying at the Rotterdam Conservatory.

[80] They performed additional shows in the Netherlands, but disagreements between van Leer and Ruiter over material intended for an official release effectively split up the group, in 1999.

[83] After some well received gigs in the Netherlands, the group resumed the Focus name and acquired Willem Hubers as their new manager and booking agent which led to several offers to perform worldwide.

The advert aired on television worldwide which generated renewed interest in the band and led to "Hocus Pocus" entering the UK Singles Chart at number 57.