In Peter S. Beagle's book "We Never Talk about My Brother," the quote "Envy nobody. It is the true secret of happiness, or at least the only one I know" conveys a profound insight about contentment and personal well-being. The idea is that harboring envy can lead to unhappiness, while letting go of jealousy enables an individual to appreciate their own life and be at peace. It highlights the importance of embracing one's own journey, rather than comparing it to others.

The message encourages readers to focus on their unique experiences and successes. By releasing feelings of envy, one can cultivate happiness and fulfillment in life. This perspective suggests that true joy comes from within and is not dependent on the achievements or possessions of others. Overall, Beagle’s words serve as a reminder that the path to happiness lies in acceptance and self-contentment.