The series

Nine books. One mechanism.

The body builds itself once, from signals modern life now forges.

The Domain books

One signal, one window: what happens when an input the body builds from is forged or lost.

The Window That Only Opens Once: A century of industrial chemistry reached you before birth. The prenatal window, when a body is built once. Industrial chemicals read as the body's own hormones.
The Window That Won't Open: Every morning the Pill tells your body it is already pregnant. The fertile years, when the monthly cycle is held on one note. A prescribed hormone signal the body reads as pregnancy.
The Window You Can't Look Away From: The real thing loses to a caricature of itself. The adolescent reward system, still being built. The supernormal stimulus: a brighter fake of the real thing.
The Window That Went Missing: The immune system was starved of a truth it needed. Early life, when the immune system learns what to tolerate. A missing signal: the microbes the body expected.
The Window That Won't Turn Off: The oldest question any creature answers: what time is it? The developing clock. Artificial light at night.
The Window That Won't Let Go: Your body defends a weight it never chose. Before birth and early life, when the defended weight is set. The food and chemicals that set the body's thermostat.

The same thesis through a new lens: the grandchildren who inherit a mark, and the money that prices in the harm.

The Window That Never Closes: You already wrote a second will, without a pen. A window into the future: the generations after. A mark on how a gene is read, passed down.
The Window in the Boardroom: A poisoned generation is the system working, not failing. A window into the money. The incentive that keeps harm in production.

The thread under the other eight. Best read last.

The Window Was Fake the Whole Time: One claim added to the eight books before it: they rhyme. Every window in the series, read together. The counterfeit: the one mechanism under all of it.