In the early hours of the morning, having trudged through what seemed like a never-ending tunnel in interminable darkness, two adventurers sat down dejectedly and sighed with resignation. "It's useless," one said, "We'll never get out."

The other adventurer, always an optimist, shrugged it off. "Never fear," he shouted, "There is always light at the end of the tunnel."

Miraculously, as he spoke, the second adventurer glanced upward, and saw to his great surprise and jubilation a light that grew steadily brighter. "Look!" he exclaimed, "There's still hope!"

It was only then that they noticed it was the light of an approaching train.

Light at the end of a tunnel can take several different forms. On one level, it may be achieving a hard-earned goal in the fields of sport or academia. On another, it may be attaining something for the...