For years, she had been losing hair and weight. She had started forgetting whole days, and sometimes appeared to be in dreamlike trances. Her children and friends worried she had Alzheimer’s.

But in late 2020, after she was summoned to a police station in southern France, she learned a far more shattering story.

Her husband of 50 years, Dominique Pelicot, had been crushing sleeping pills into her food and drink to put her into a deep sleep, the police said, and then raping her. He had ushered dozens of men into her home to film them raping her, too, they said, in abuse that lasted nearly a decade.

Using the man’s photographs, videos and online messages, the police spent the next two years identifying and charging those other suspects.

On Monday, 51 men, including Mr. Pelicot, will go on trial in Avignon, in a case that has shocked France and cast a spotlight on the use of drugs to commit sexual abuse and the broader culture in which such crimes could occur.

The accused men represent a kaleidoscope of working-class and middle-class French society: truck drivers, soldiers, carpenters and trade workers, a prison guard, a nurse, an I.T. expert working for a bank, a local journalist. They range in age from 26 to 74. Many have children and are in relationships.