Jonas Ekfeldt is a Swedish music producer and singer. Won acclaim in 1996 using the name Robin Cook and the breakthrough single "I Won't Let the Sun Go Down" (a cover of Nik Kershaw's debut "I Won't Let the Sun Go Down on Me") followed by "Comanchero" and the album Land of Sunshine in 1997.

Ekfeldt sang and produced "I Won't Let the Sun Go Down" and all subsequent releases under the name Robin Cook, but appointed Manuel Manci to front and perform, thinking he himself lacked time. The truth of who really was the singer was kept secret until Swedish newspaper Aftonbladet ran an article in 2002. Yet another single was released in 2002 under the name Robin Cook, titled "Susanna" with Ekfeldt on the cover.