Palm trees are the life support the desert oasis.  It used to be that a family needed a minimum of sixteen palm trees to survive.  In the Empty Quarter of Saudi Arabia, there are still oases at which the traveler aims, and the palm trees there determine whether he will go on or not.  

The palm tree is so much a part of Arab cultural imperative that, to this day, you will often receive a courtesy round of dates and camel's milk upon arrival in the home of desert Arabs of any wealth or class.

This graphic appears at the end of every chapter in the printed book which ends on a left hand page.