One of the easiest and therefore most common ways to communicate with spirits is by asking them to tap out their answers by encouraging them to tap once for "yes" and twice for "no." It doesn't require the use of a Ouija board, a spirit box, or any other equipment. You can also ask the spirits to tap out how many of them are present. Or you can write down the letters of the alphabet and run your finger over the letters, asking the spirit to tap to indicate the letter you're pointing at in order to spell out a word, sentence, or date.

The first recorded case of rapping as a way of communicating with ghosts dates back to New York in 1848. Two sisters, Kate and Margaret Fox, were just 12 and 15 years old when they moved with their family to a new house and experienced frequent unexplained...