during the latter half of the 1960s southern worked on the screenplays of a string of "cult" films. his credits in this period include "the loved one" (1965), "the collector" (1965), "the cincinnati kid" (1965), "casino royale" (1967), "barbarella" (1968), "easy rider" (1969), "the magic christian" (1969), and "end of the road" (1970) .