Joke about dream

A young woman was taking an afternoon nap.
After she woke up, she told her husband, "I just dreamed that you gave me a pearl necklace for Valentine's Day. What do you think it means?"
"You'll know tonight," he said.
That evening, the man came home with a small package and gave it to his wife.
Delighted, she opened it, only to find a book entitled "The Meaning of Dreams."