The Swiss band Krokodil from Zurich was founded in late 1968 by Düde Dürst (dr) and Hardy Hepp (vln, p, voc). Together with Walty Anselmo (g, sit, voc), Mojo Weideli (harp) and the Englishman Terry Stevens (b, voc), they produced several demo recordings. These led to a record deal with the German branch of the US label Liberty. They recorded their eponymous debut album in May 1969 in Munich's Trixie Studios, produced by Siegfried E. Loch. With their blues-orientated, partly hard rock with various progressive overtones and soft folk passages, led by Mojo Weideli's harmonica, they also attracted attention abroad. Although they came from Switzerland, they were marketed as the Krautrock answer to the English Groundhogs. However, the sales figures were disappointingly low.

After one more album, Hardy Hepp left the band to pursue a solo career and with An Invisible World Revealed they created an album that established them as the leading and best Swiss progressive rock band. Their first album of the same name, designed by Düde Dürst, is extremely rare today as a German Liberty original.