The Santaroga Barrier
Frank Herbert
 A psychologist, Gilbert Dasein, is hired by corporate interests to investigate a town in a valley where marketing seems totally ineffective: Outside businesses are allowed in, but wither quickly for lack of business. Santarogans aren't hostile, they just won't shop there; neither are they xenophobic, instead appearing maddeningly self-satisfied with their quaint, local lifestyle. Adding an element of danger, the last few psychologists sent in have all died in accidents that are (seemingly) perfectly plausible. Complicating matters further still, the psychologist's college girlfriend, Jenny, has returned to Santaroga. With this in mind, Dasein cautiously enters the town and quickly discovers 'Jaspers', an additive to the food and drink commonly ingested in Santaroga that seems to imbue the consumer with greater health and an expanded mind. Those who consume it don't become psychic; instead, they're simply far more lucid than the average citizen of the U.S, although there are numerous hints at a group mind operating at a subconscious level. Their newspapers are vaguely subversive with their folksy, enlightened commentary on world affairs; their dinner conversations knowledgeably reference great theories of psychology, politics, and cognitive science. Soon, Dasein is having narrow misses with perfectly plausible accidents: A boy playing with a bow and arrow releases it; the lift under his car in a garage collapses; a waitress in a diner accidentally uses insecticide rather than sugar for his coffee. Knowing that Jaspers creates exceptionally perceptive, penetrating individual minds, Dasein realizes that he has offended a communal id that feels threatened by him. As Jenny tries to convince him to settle down with her there, he wonders whether he'll live long enough to decide.