Rachel Scott and her killer Eric Harris both talked about starting a -chain reaction.- Eric used violence to kill and destroy at Columbine High School. But Rachel chose another path. In a personal creed she wrote one month before her death in the Columbine tragedy, she explained her conviction that if one person goes out of his or her way to show compassion, it will start a world-changing chain reaction of kindness.

For Rachel, this was a solemn calling. And now her father, Darrell Scott, is carrying on her crusade by challenging people of all ages to commit themselves to creating a...