Just Say Boo! by Susan Hood
I love Just Say Boo! The pictures look like they are from a beautiful, platonic New England-y (or Pasadena-y) suburbia where neighborhoods are full of kids and everyone dresses up — kids and adults — in homemade costumes and goes trick-or-treating at twilight. It’s like a fantasy childhood Halloween. The book teaches kids what to do if they get a little scared by all the Halloween decorations and costumes (Just say “Boo!”), and the rhythm and rhyme of the words makes it fun to read out loud over and over. Little ones can chime in with a “Boo!” every other page or so.