Katar (novel)

Katar is a novel by Stanislaw Lem, published in 1975. It brings up topics like the international terrorism and chemical warfare.

Warning: Wikipedia contains spoilers!

A former astronaut is hired by a detective agency to help in an investigation of a case of mysterious deaths. Several victims became mad and committed suicide during their vacation in Napoli, apparently without reason.

During the investigation, it becomes apparent that certain innocent factors can be combined into a strong depressor, a kind of chemical weapon. The hero experiences its effects, however his training helps him to survive and solve the case.