Marcel Karl Jacob was a Swedish musician, best known as the founder, chief songwriter, and bassist of the hard rock band Talisman. For a brief period, he also played in the band Europe and with Yngwie Malmsteen. Jacob was also a skilled lead guitarist, occasionally playing guitar solos on albums where he felt the guitarist did not perform to his standards.

Talisman was a Swedish hard rock band. Founded in 1989 by the songwriting bassist Marcel Jacob and fronted by the American singer Jeff Scott Soto, the band released seven studio albums from 1990 to 2006, before going on a farewell tour in 2007. While mainly described as hard rock and heavy metal, the band's sound had also been influenced by a variety of genres outside the rock music scope, such as rhythm and blues, soul, and funk in particular.