With the increased use of ethnic and fusion-style elements such as the sitar, tablas and flute, the quartet Krokodil (without Hardy Hepp) from Switzerland expanded their West Coast and blues rock roots with additional musical expressions. For the recordings of their third album An Invisible World Revealed, they added a Mellotron, which was available in the studio of the legendary producer Dieter Dierks. He is also regarded as the fifth member of the band, as he played a major part in this change of direction by encouraging the band to try out new sounds and ideas and even contributing on the electric piano in some tracks. Building on their blues-rock foundation, they experimented with various styles, ranging from progressive hard rock and laid-back West Coast jams to Far Eastern influences and psychedelic sounds.

The band had by now reached a level of virtuosity that very quickly made this album, released in Germany by United Artists Records in November 1971, a milestone of early 1970s progressive rock. With its attractive artwork by drummer and graphic designer Düde Dürst, who was also responsible for the cover design of their debut album, it is regarded as their finest work and has since enjoyed the highest reputation among collectors from all over the world. This Swiss group of talented musicians, renowned for their technical mastery, went on to produce two further albums before finally disbanding in 1974.