One of the the most instrumentals I ever enjoyed. The idea of the song "The Call Of Ktulu" is based upon H.P. Lovecraft's sole book "The Shadow over Innsmouth" which was first introduced to the rest of the band by Cliff Burton. The spark of beeing fascinated by the book began quickly spreading over the rest of the band. The song's name was taken from one of H.P. Lovecraft's main story featuring Cthulhu "The Call of Cthulhu" which has been written in 1928 for the magazine "Weird Tales". The name "Ktulu" is originally written "Cthulhu" by H.P. Lovecraft.