"I just had a dream about it" joke

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".