The novel explores the effects of mass automation on society. And unlike some sci fi novel set in a far distant future, it's set in the present. This isn't the Bulterian Jihad a thousand years in the future. It's set in the here and now in our world.

In Manna, the machines don't rise up and take over the world. Paperclip maximizers don't run out of control and kill everyone. AI alignment isn't even a problem considered in the novel. The novel explores the societal effects of the tech working completely as designed.

Automation gets deployed more and more. What jobs remain become increasingly dehumanized. Increasingly jobs are just literally being a meat robot for the computer. When working at a place like McDonalds, you put on a headset. The restaurant's computer system tracks you through the day, micromanaging your time down to the second. It tracks every minor work action you perform. This starts in restaurants and customer service, but ultimately grows out from there to nearly all wage and salary jobs. This novel was written in the 2000s, but it predicted a lot of the algorithmic debasement we've seen with companies like Uber, Lyft, and Amazon and the slopification of jobs such as programming. Jobs also become more and more scarce, and the credit rating system becomes ever more onerous and interconnected. Pretty soon almost every employer is sharing the same employment records. If you get fired too many times, the central system blackballs you and you become unemployable.

This mass automation results in the vast majority of the population of the US being rendered destitute. Either to avoid rebellion or out of some limited sense of morals, the ownership class comes up with a solution. We don't get UBI. We get fully automated luxury communism.

The same automation that impoverished the populace also makes it very cheap to construct mass-produced buildings. The federal government scoops up vast swathes of empty land in places like Western Kansas and the Nevada desert. This is where the surplus population is warehoused. The government uses automated construction to build giant high rise complexes hundreds of miles from any work opportunities or population centers. They're basically giant dorms in the middle of nowhere. You have a simple space with a bed, desk, and entertainment. You live with a roommate. You eat in a communal cafeteria. The buildings are maintained, the interiors cleaned, and the food all prepared through automated systems. These aren't prisons per say. The people in them aren't being punished. They're simply being stored somewhere where they won't bother the wealthy. Imagine a vast building the size of a city's downtown and many stories tall. A single building capable of housing millions in a vast windowless labyrinth. This is the reality for most of the population. You get a roof over your head, a bed to sleep in, a nutritionally sufficient diet and unlimited access to tv, video games, etc. Bread and circuses on a mass scale.

And moving to one of these facilities is not voluntary. If you lose your job, you have a short window to find another, demonstrate some other source of income or independent wealth, or be ticketed and arrested for vagrancy. The old vagrancy laws are brought back in force, and the vast majority of the population ends up being dumped into these facilities.

Once there, escape is nearly impossible. There are no walls or armed guards. But the only real way out is to have someone on the outside come and sign paperwork saying they're willing to support you financially. You're allowed to walk out the door and meander the trails around the buildings. But if you wander too far, a sentry robot comes up and starts giving you vague warnings about it being dangerous to go further. Keep going and you'll find yourself knocked out by a tranquilizer dart and wake up back in your dorm room. And there's no real way to apply for work. The few people with jobs on offer aren't looking for people trapped in these facilities. Unless you have some caring financially independent relative willing to take you in, you're trapped in the government dorms forever.

The novel describes how this was a deliberate choice to manage the excess population. The characters mention that the facilities are built tightly enough and isolated enough that if the destitute in these complexes ever rose up in rebellion, the government could just drop a couple of hydrogen bombs on them. They could completely eliminate the excess population in an hour with no collateral damage to anything else. Individual dorms are sex-segregated, and those couples that do still manage to form report that any attempts at having children are unsuccessful. They conclude that birth control drugs must be in the food or water.

In Manna, automation finally forces the US to build a proper welfare state. But automation also makes it possible to do so cheaply. And the US has never been known for its compassionate treatment of the destitute. The government doesn't leave everyone to starve. It just warehouses everyone, keeps them from reproducing, and lets the problem solve itself in time. You never have to fear physical deprivation. You will not starve or die of exposure. But you lose absolutely any bit of control or agency over your own life. The government isn't supporting you. It's storing you somewhere out of the way where you can't cause any trouble.