Grandchildren are a time machine. No matter what their age, you can relate to your being the same age in the past. Memories otherwise inaccessible become accessible. Suddenly, you are 6 years old and about to explore the worldly world of the first grade. Unlike being actually 6 years old, you can escape the world of a 6-year-old by the blink of an eye. Present is the emotion of nostalgia without the fear of the unknown. A grandchild simply continues to be a grandchild. As a grandparent, and as a former grandchild of living grandparents, I can enjoy both worlds. The perfect remedy for being tense about the present tense. — Leon Campbell lives in La Jolla.