On July 26, 2022, as I was living through a period of acute loneliness despite being a naturally solitary person, NASA reported that computer modeling of data from its Lunar Reconnaissance Orbiter (LRO) had revealed several cylindrical pits on the Moon with just the right shape to be shaded just the right amount to offer shelter from the extremes of the lunar surface. Because the Moon has no atmosphere to act as its thermostat, its temperature fluctuates dramatically as it faces and turns away from the Sun, rising to 260°F (about 127°C) in the daytime and plummeting to -280°F (about -173°C) at night. But these unique nooks, which are most likely collapsed lava tubes, are a cozy 63°F (17°C) inside — he feeling-tone of a crisp autumn day in Brooklyn, where I live. Images from the LRO suggested that these pits might unfold into caves that would make perfect sites for lunar exploration — campsites with a stable temperature, more protected from cosmic rays, solar radiation, and micrometeorites.

There is something poetic in knowing that we evolved in caves and might one day inhabit caves on another celestial body, having invented the means to get there with the imagination that bloomed over millions of years in the lonely bone cave of the mind.

There is also something poetic in knowing that as we fantasize about leaving for the Moon, the Moon is leaving us.

The prolific English astronomer Edmund Halley first began suspecting this disquieting fact in the early 18th century after analyzing ancient eclipse records. Nobody believed him — the Moon looked so steady, so unlosable. It took a quarter millennium for his theory to be vindicated: When Apollo astronauts placed mirrors on the lunar surface and when laser beams were beamed a them from Earth, it was revealed that the Moon is indeed drifting away from us, at the precise rate of 3.8 centimeters per year — more than half the rate at which a child grows.

The Moon is leaving us because of the gravitational conversation between it and the Earth: the ocean tides. The drag they cause slows down the planet’s spin rate. Because gravity binds the Moon and the Earth, as the Earth loses angular momentum, the Moon overcompensates in response; as it speeds up, it begins slipping out of our gravitational grip, slowly moving away from us.

We know this thanks to Albert Einstein’s theory of general relativity — the revelation that space is not flat, time is not absolute, and spacetime is a single fabric along the curvature of which everything, including light, moves.

I thought of Einstein, who at sixteen, lonely and introverted, began wondering about the nature of the universe by imagining himself chasing a beam of light through outer space; I thought of the poet Rainer Maria Rilke, also lonely and also dedicated to the light, who at the same time was formulating his general theory of love as “two solitudes that protect, border, and greet each other.” And I thought about how love is simply the solitary light between people, neither partitioned nor merged but shared, to light up the sliver of spacetime we have each been allotted before returning our borrowed stardust to the universe.

Somehow it all felt like a children’s book that didn’t yet exist. So I wrote it, having always believed that every good children’s book is a work of philosophy in disguise, a field guide to the mystery we are a part of and the mystery we are — in the language of children, which is the language of curiosity and unselfconscious sincerity, such books speak the most timeless truths to the truest parts of us by asking the simplest, deepest questions to help us understanding the world and understanding ourselves so that we may be more fully alive.

By one of those wrinkles in time and chance that we call luck, shortly after I sent the manuscript to my friend Claudia at Enchanted Lion Books, I received a lovely note from a stranger named Sarah Jacoby in response to my essay about Margaret Wise Brown’s complicated love with Michael Strange. Sarah told me that she too had fallen under the spell of their singular love while illustrating a picture-book biography of Margaret. I ordered it and, enchanted by Sarah’s soulful watercolors and tender creatures, spontaneously invited her to illustrate my lunar story of loneliness and love on nothing more than an instinct of creative kinship. She must have felt it too because, felicitously, she said “yes.”

And so The Coziest Place on the Moon (public library) was born.

This is how it begins:

It was on a Tuesday in July that Re woke up feeling like the loneliest creature on Earth and decided to go live in the coziest place on the Moon.

At exactly 7:26 — a pretty number, a pretty hour — Re mounted a beam of light and sailed into space.

It took exactly 1.255 seconds, because light travels at the speed of dreams, to land exactly where Re wanted to land.

Across Sarah’s enchanted spacescapes, Re has a surprising encounter that takes the story to where it always wanted to go — a reckoning with how to bear our loneliness and what it really means to love.