There are several passages in the new book “Overloaded and Underprepared” that fill me with sadness for American high school students, the most driven of whom are forever in search of a competitive edge. Some use stimulants like Adderall. Some cheat.

But the part of the book that somehow got to me most was about sleep.

It’s a prerequisite for healthy growth. It’s a linchpin of sanity. Before adulthood, a baseline amount is fundamental and nonnegotiable, or should be.

But many teenagers today are so hyped up and stressed out that they’re getting only a fraction of the rest they need. The book mentions a high school in Silicon Valley that brought in outside sleep experts, created a kind of sleep curriculum and trained students as “sleep ambassadors,” all to promote shut-eye.

The school even held a contest that asked students for sleep slogans. The winner: “Life is lousy when you’re drowsy.”

Sleep ambassadors? Sleep rhymes? Back when I was in high school in the 1980s, in a setting considered intense in its day, the most common sleep problem among my peers was getting too much of it and not waking up in time for class.

Now the concern isn’t how to rouse teens but how to lull them. And that says everything about the way childhood has been transformed — at least among an ambitious, privileged subset of Americans — into an insanely programmed, status-obsessed and sometimes spirit-sapping race.

Take one more Advanced Placement class. Add another extracurricular. Apply to all eight Ivies.

Lose a few winks but never a few steps.

“Overloaded and Underprepared,” published on Tuesday, was written by Denise Pope, Maureen Brown and Sarah Miles, all affiliated with a Stanford University-based group called Challenge Success, which urges more balanced learning environments. The book looks at homework loads, school-day structures and much more.

And it joins an urgently needed body of literature that pushes back at helicopter parenting, exorbitant private tutoring, exhaustive preparation for standardized tests and the rest of it. This genre goes back at least a decade and includes, notably, Madeline Levine’s “The Price of Privilege” and Paul Tough’s “How Children Succeed.”

But it has expanded with particular velocity of late. “How to Raise an Adult,” by Julie Lythcott-Haims, came out last month. “The Gift of Failure,” by Jessica Lahey, will be released in two weeks.

There’s a unifying theme: Enough is enough.

“At some point, you have to say, ‘Whoa! This is too crazy,’ ” Pope, a senior lecturer at Stanford, told me.

Sleep deprivation is just a part of the craziness, but it’s a perfect shorthand for childhoods bereft of spontaneity, stripped of real play and haunted by the “pressure of perfection,” to quote the headline on a story by Julie Scelfo in The Times this week.

Scelfo wrote about six suicides in a 13-month period at the University of Pennsylvania; about the prevalence of anxiety and depression on college campuses; about many star students’ inability to cope with even minor setbacks, which are foreign and impermissible.

Those students almost certainly need more sleep. In a study in the medical journal Pediatrics this year, about 55 percent of American teenagers from the ages of 14 to 17 reported that they were getting less than seven hours a night, though the National Sleep Foundation counsels 8 to 10.

“I’ve got kids on a regular basis telling me that they’re getting five hours,” Pope said. That endangers their mental and physical health.

Smartphones and tablets aggravate the problem, keeping kids connected and distracted long after lights out. But in communities where academic expectations run highest, the real culprit is panic: about acing the exam, burnishing the transcript, keeping up with high-achieving peers.

I’ve talked with many parents in these places. They say that they’d love to pull their children off such a fast track, but won’t the other children wind up ahead?

They might — if “ahead” is measured only by a spot in U-Penn’s freshman class and if securing that is all that matters.

But what about giving a kid the wiggle room to find genuine passions, the freedom to discover true independence, the space to screw up and bounce back? Shouldn’t that matter as much?

“No one is arguing for a generation of mediocre or underachieving kids — but plenty of people have begun arguing for a redefinition of what it means to achieve at all,” wrote Jeffrey Kluger in Time magazine last week. He noted, rightly, that “somewhere between the self-esteem building of going for the gold and the self-esteem crushing of the Ivy-or-die ethos, there has to be a place where kids can breathe.”

And where they can tumble gently into sleep, which is a gateway, not an impediment, to dreams.