Producer Irvin Shapiro suggested the change to The Evil Dead because he feared "Book of the Dead" sounded too academic for a horror audience.
The film was initially titled Book of the Dead , inspired by writer-director Sam Raimi’s interest in H.P. Lovecraft.
Five college students (including Ash Williams , played by Bruce Campbell) vacation in an isolated Tennessee cabin where they discover the Necronomicon Ex-Mortis (the Book of the Dead) and an audio tape of demonic incantations.
Old School Review: “The Evil Dead” (1981) - spacecortezwrites
The third installment dropped the "Evil Dead" prefix entirely in its primary title, though it is the direct conclusion to the original trilogy.