SPOILER: sent in by Dallas E.

This book follows the exploits of a couple who see the present day world turned upside down.  An unseen force has attacked the Earth and taken a vast majority of people. They have disappeared from the face of the Earth.
 
The important clue to the conclusion of the book is how witnesses (all children) describe how the adults are taken and how the adults react to being taken.  The children describe the abductions as either the adults are lifted up and through seemingly solid objects or pulled down, again through seemingly solid objects.  The adults going up are happy and peaceful, while the adults going down are fighting, kicking and screaming.
 
That's right - the 'Force' is both the Devil and God. The Devil has taken those who are bad while God has taken those who were good.  Those people left behind are those who must rebuild Earth.  All the children and a select number of adults who are inherently good and who have the right education to see that civilization will carry on.
 
Basically, it is a modern day description of the flood of Noah's time.
 
I liked the book