CREATE TABLE table_75012 ("Vol. #" FLOAT, "Title" TEXT, "Material collected" TEXT, "Publication date" TEXT, "ISBN" TEXT)

How many Volume Numbers have the title of Darkness Falls?
SELECT SUM("Vol. #") FROM table_75012 WHERE "Title" = 'darkness falls'
SELECT SUM("Vol. #") FROM "table_75012" WHERE "Title" = 'darkness falls'