Hard one. I'll list a few I suppose

The terminal man by Michael chrichton: a paranoid man has electrodes implanted in his head to stop violent fugue states he enters, but he learns to control the electrodes, and accidentally sets off significantly more intense violent outbursts

Annihilation by Jeff vandermeer: the first part of the southern reach trilogy, an expedition of scientists are sent into a possibly alien anomaly to find out what it is and how to stop it from growing and consuming the land. The environment inside is confusing and seems to infect anyone inside it in some way.

Wizard and Glass by Stephen King: the fourth book in the dark tower series, it's a flashback to the main characters adolescence, his first mission as an ambassador and spy for his kingdom to find out how a small town may be secretly participating in a civil war, and how a witch may be controlling the enhabitants.

The Stranger by Albert Camus: a man with no motivation or real concern finds himself the focus of a murder trial, and without any interest in defending himself, can't see how nobody is on his side.