ANNA LIVES IN SUNNYVALE, CALIFORNIA, in a housing development built in the sixties. In a subdivision that supplanted a citrus grove in what was then called the Valley of Heart's Delight. In an uninspired house that was a forerunner of the barracks that would soon obliterate all the fields and orchards and give rise to a new name for the region: Silicon Valley.

Anna's street has twenty-five houses on it, but just four house models: a rancher, a colonial, a Cape Cod, and a split-level. Over the years people have added decks and landscaping, enlarged the windows and converted garages, but the skeletons of the original structures remain. When a light goes on upstairs in the colonial diagonally across the street, the mirror image of Anna's own home, Anna knows that Janie Poole, thirteen years old, has taken refuge in the bathroom to avoid the squalling of her newborn twin brothers. If the hall on the bottom floor of the split-level next door is suddenly illuminated in the late evening, Mr. Johnson is helping Mrs. Johnson to the master bedroom after she's enjoyed one scotch too many. There are no secrets, no mysteries, in this suburban enclave.

The Sunnyvale Post Office knows Anna's block as the Street of Children's Names. A year before Anna was born, the city dug up and re-poured the sidewalks. The glistening gray virgin squares proved too tempting to the neighborhood children, who carved their names in the still-wet concrete. Their engravings remain today, are writ large along the block. Each letter covers an entire pavement panel, and over the years the residents have come to call the houses by the children's names rather than their numerical addresses. Anna lives in S-A-R-A-H with her mother and father. The Goldschmidts live in K-A-R-I-S. Jim Fulson, the only child of that epic effort still living on the block, can be found across the street in C-A-R-O-L-I-N-E. The foul Hendersons next door to him in C-L-A-I-R-E.

Most lights are out by midnight on the Street of Children's Names. Everyone in bed by 11:30 pm. Except Anna. She ghosts in the early morning. No respite. Up at 3 am, unable to sleep. Too agitated to lie in bed. An uncalm insomnia. Her mother tries everything — chamomile tea, hot milk, even pills. Those Anna flushes down the toilet. She knows there must be a reason for her to be awake at such an hour. She is waiting for answers. Until then, she is resigned to witness the death of each successive night. To acknowledge the arrival of each new day. To prepare for whatever follows.

ANNA IS SIXTEEN WHEN THE darkness descends.

She had hints that it was coming. Interludes of deep sadness over the past twelve months. Mourning, almost, triggered by the smallest things. An expression flitting across her father's face as he gazed at her mother. A glimpse of a small boy waiting alone at a bus stop. But the sadness always dissipated, she would always come to, and find herself again. Until now.

The morning it all changes, the problem starts with the mirror, still plastered with pink Disney princess stickers, smudged from practice kisses. She looks at her reflection and retches. A sudden, violent aversion. What. Is. That. Thing.

Only the previous evening, she'd stood naked in front of her mirror — just so — appreciating her shoulders, her breasts, her waist, admiring her long blonde hair. Her recent makeup purchases were scattered on the bureau: cheap Maybelline, L'Oréal from Walgreens. Because I'm worth it. Those were the articles of faith of her peers, their most fervent beliefs, and Anna had been trying to subscribe to them, trying to blend in. "People like us, we pretend. We fake it, until we're into our twenties," her mother told her. "Then we come into our own. Then our weirdnesses become our strengths." Anna had had one of her flashes of despair at this, but her mother hadn't noticed, was looking straight ahead while driving, her hands steady on the wheel. Their most intimate talks, of which this was one, occurred while her mother was preoccupied with other things.

Anna can't bear to look at herself now. She covers her mirror and turns all the photos of herself to the walls. Her mother gives up turning them back after the fifth day. Both she and Anna's father are openly concerned. Whispering stops whenever Anna walks into the room. She begins wearing her Stanford sweatshirt everywhere, the peaked hood drawn tight around her head, over her ears, pulled down to cover her forehead. Anna's mother tries to make light of it. "Hello, Grumpy," she says. "Or is it Bashful?" but Anna is as receptive to human interaction as a slab of meat.

Depression, they call it. Such a flat name for such a ferocious and uncompromising beast. Anna prefers the medieval term. Melancholia. Black bile. A foul humor that steals into your joints, paralyzes your muscles, immobilizes your bones. But it also clears your vision, reveals the truth that everything is tainted, and that you are worse than untouchable. An obscenity.

At school, first: What's wrong, Anna? Then increasingly, sullenly, even from her friends: What's your problem? A couple of phone calls. A dramatic attempt at intervention. Then, nothing. Three weeks later Anna is where she needs to be: alone.

But Anna's body is the true enemy. A heaviness of limbs. She can barely lift her head from the pillow in the morning. Melancholia. Transforming her into a machine for manufacturing despair. It is hard to breathe. Why breathe.

Anna cycles through the rote motions of an automaton. Her day shaped by invisible orders by an invisible commandant. Wear this. Eat this. Look this way. Now look down. Shake your head no. Say not a word. Turn. Turn and leave the room.

Then, one morning, at the breakfast table. Staring at the milk carton. Then. There it is. Her path forward. Expiration date. Heat spreads across Anna's face. Her fingers tingle. Her expiration date. Anna does not yet know the exact day and time. But it is coming. It will come. She will be released from pain.

IT IS AROUND THIS TIME that Anna's mother decides to start a reading regime at bedtime. Anna feebly protests — "I'm sixteen!" — but lacks the energy to prevail. Her mother is adamant. She chooses an old Bible that once belonged to Anna's grandmother. "This gives us some time together," she says. "Besides, you're not truly educated if you don't know your biblical stories. You won't understand literary references. Or great works of art or music. Or what religious nutcases are talking about in election years." Until this point, Anna has learned nothing about God. "Religions are the work of the devil," her mother is fond of saying, without irony. In the throes of her melancholia, and ultimately grateful for any attention her mother deigns to give her, Anna acquiesces when her mother opens the book and begins to read.

In the beginning God created the heaven and the earth ...

So Anna learns about the creation of the world, about Adam and Eve, but as metaphors, not truths. The snake stands for temptation. The apple for knowledge that humans should not possess. Anna doesn't blame Eve for coveting it. She would have coveted it, too.

Anna finds she enjoys thinking that powers exist greater than herself. She recognizes Satan's determination and ruthless single-mindedness. Both her parents have it, each in their own way. They usually gaze past Anna to focus...