Would knowing the weight of your soul help you master it? If the stretch of all your DNA combined could carry you to the moon and back, could it also carry the genes to empower you to reach the stars? If you changed the numbers embedded in your physical life, would the essence of your life change? 'Twenty-one Grams of Spirit and Seven Ounces of Desire tries to make the case, through sixty-four pieces that while measure is not meaning, it helps shape it. This collection captures the struggle to make sense of measures that science is known for and goes further by speculating on what they could mean in our lives, and not just in the closeted halls of science labs and institutions. It is divided into three parts: The Three-meter Inheritance, which contains pieces on the genetic inheritance that lurks inside each of us--three meters long in each of our cells--and how this length plays out in the tales of our lives; The Sway of the World, which is about the measures of the world outside us, and how they affect the rhythm and the tune of our lives; and The Tug-o-War, which gathers essays that describes the drama where genes, the world and the human spirit take turns in surrendering to each other. This collection is a suitcase of rulers, weights, and light meters taking their place alongside humanity's spread of will, talent and emotion, in the hope that in some spots, every now and then, there would be even a hint of meaning, even if only in passing.