The publisher provided the following excerpt of "Why Him? Why Her?: Finding Real Love by Understanding Your Personality Type," by Helen Fisher, to ABC News.
Watch an hour on the science of attraction Friday on a special edition of "20/20" at 9 p.m. ET
Chapter 1: Eavesdropping on Mother Nature
"I am large, I contain multitudes." -- Walt Whitman
"Now you will feel no rain, for each of you will be shelter to the other. Now you will feel no cold, for each of you will be warmth to the other....Full Story