The Calculus of Closeness

"Your crackle is exhausting," Nils says.

Greta stares at him. "My what?"

So begins a fight that will only make sense two hundred pages later-after we've gone back to the beginning, to a gallery basement where a woman covered in paint stood in a waveform she couldn't name, and an engineer saw something he couldn't explain.

The Calculus of Closeness is a book about derivatives. It's also a book about love. Surprisingly, these turn out to be the same thing.

Nils is brilliant, analytical, and deeply uncertain how to navigate a relationship with someone as volatile and vivid as Greta. So he does what he knows: he builds a framework. Position measures closeness. Velocity measures whether you're drifting together or apart. Acceleration, jerk, snap, crackle, pop-each derivative captures finer dynamics, subtler patterns, the texture of how relationships actually change.

Through six years of crisis and repair, diagnosis and medication, a move to Zurich, a pregnancy, and the irreducible complexity of becoming a family, Nils learns what the math can and can't do. It can teach you to pay attention. It can give you vocabulary for the ineffable. It can't give you control.

This is a book about relationships written by the kind of person who needed calculus to understand them. The math is real. The love story is fiction. The confusion is universal.

For overthinkers, engineers of the heart, and anyone who's ever suspected that feelings might have an API.