What is the name of one of the best-known novels by the Brazilian writer Paulo Coelho?

Paulo Coelho de Souza (born 24 August 1947) is a Brazilian lyricist and novelist. He is a member of the Brazilian Academy of Letters.

At 17, Coelho's parents committed him to a mental institution from which he escaped three times before being released at the age of 20. At his parents' wishes, Coelho enrolled in law school and abandoned his dream of becoming a writer. One year later, he dropped out and lived life as a hippie, traveling through South America, North Africa, Mexico, and Europe and started using drugs in the 1960s.

"Veronika Decides to Die" tells the story of Veronika, a 24-year-old Slovenian who appears to have everything in life going for her, but who decides to kill herself. This book is partly based on Coelho's experience in various mental institutions, and deals with the subject of madness. The gist of the message is that "collective madness is called sanity".