Didn't we just do this thread a couple weeks ago? Deja Huh? Big front runners were Exorcist, It, and Pet Semetary? Yeah...but who cares? These questions are always fun, so...
Instead of Exorcist, or any King, this time I'll say...uh...well, tell the truth, the book that scared me the most, when I was about five, was some Time-Life crime volume featuring a lengthy section about the Manson murders--with pics (piggies on the wall in dried blood, corpses--real ones). My older sister, bless her morbid heart, read and explained the whole thing to me. Had nightmares about evil, dirty hippies breaking in and killing my entire family for WEEKS. Thanx, sis.
You reminded me. I keep meaning to read The Stranger Beside Me by Ann Rule.