Bring your fingertips to the side of your neck. Find the pulse.
That steady knock is your heart pushing blood through an artery. The blood carries iron. A lot of it. Every red cell is packed with a molecule called hemoglobin, and every hemoglobin molecule is built around four iron atoms that bind oxygen, let go of it, and bind it again — one grip, one release, once every few seconds, for every minute of your life.
You can taste it, if you want to. Cut yourself, or bite your tongue, and the metal in your blood arrives on your tongue as rust.
Now here is what almost no one thinks about at that moment.
The iron was made in a star.
Not figuratively. Not as a metaphor for the vastness of things. In the ordinary, literal sense: every iron atom in your body was forged in the core of a star that lived and died long before the Earth existed. The calcium in your bones, the same. The phosphorus in your teeth. The oxygen you are breathing as you read this sentence. Every element in your body heavier than helium — which is almost all of you — was made inside a star.
You are, in the most literal sense available to language, star material. So is the floor under your feet. So is the dog asleep at the end of the hall. So is the iron in the rail of the train you took last week. So is every cell that has ever lived on this planet.
That is where the book begins. Before anyone could be born. Before this planet, or any other, existed.