When Mormon missionaries (properly called Latter Day Saints or simply "LDS") come to your door, they will often offer a free copy of the Book of Mormon and tell you about its author, Joseph Smith. Smith, they will say, translated the Book of Mormon from golden plates he dug up in a hill in New York in the early 1800s. This is supposed to confirm his calling from God as the new prophet on the earth in these latter days. Further, they will tell you that the Holy Ghost will confirm the truth of the Book of Mormon by producing good feelings in you. Next will come the invitation to "read the Book of Mormon, pray, and ask God to show you it is true." Of course you must do this with sincerity, or it won't work.