All Flesh Is Grass — Clifford D. Simak

Long before Under the Dome, this novel of a town trapped within an invisible force field earned a Nebula Award nomination for the author of Way Station.

Nothing much ever happens in Millville, a small, secluded Middle-American community -- until the day Brad Carter discovers he is unable to leave. And the nearly bankrupt real estate agent is not the only one being held prisoner; every resident is confined within the town's boundaries by an invisible force field that cannot be breached. As local tensions rapidly reach breaking point, a set of bizarre circumstances leads Brad to the source of their captivity, making him humanity's reluctant ambassador to an alien race of sentient flora, and privy to these jailers' ultimate intentions. But some of Millville's most powerful citizens do not take kindly to Carter's “collaboration with the enemy,” even under the sudden threat of global apocalypse.
 
Decades before Stephen King trapped an entire town in Under the Dome, science fiction Grand Master Clifford D. Simak explored the shocking effects of communal captivity on an unsuspecting population. Nominated for the Nebula Award, All Flesh Is Grass is a riveting masterwork that brilliantly reinvents the alien invasion story.