From the back of the book:
YOU ARE IN ERROR. NO ONE IS SCREAMING. THANK YOU FOR YOUR COOPERATION.
The Computer is happy. The Computer is crazy. The Computer will help you become happy. This will drive you crazy. Being a citizen of Alpha Complex is fun. The Computer says so, and The Computer is your friend. Many traitors threaten Alpha Complex. Many happy citizens live in Alpha Complex. Most happy citizens are crazy. Which are more dangerous-traitors or happy citizens?
Rooting out traitors will make you happy. The Computer tells you so. If you are not happy, The Computer will use you as reactor shielding. Being a Troubleshooter is fun. The Computer tells you so. Do you doubt The Computer, citizen? Troubleshooters get shot at, stabbed, mangled, incinerated, poisoned, stapled, blown to bits and accidentally executed. This is so much fun many Troubleshooters go crazy. You work with many Troubleshooters. They all carry lasers. Aren't you glad you have a laser too? Won't this be fun?
Stay alert! Trust no one! Keep your laser handy!
When PARANOIA was first published almost 20 years ago, amid fears of nuclear war and job loss to those newfangled desktop PCs, it was instantly popular for its vision of a high-tech, post-holocaust, totalitarian future ruled by a deranged Computer. It won attention too for turning the basic paradigm of RPGs-players cooperate- on its head, making all players secret traitors who can only advance by uncovering treason.
Happily, today those fears are obsolete. Instead, we have spam, viruses, trojans, malware, distributed denial of service attacks, the RIAA, cyberwarfare, identify theft, terrorists, the Patriot Act, terrifying new diseases, the threat of environmental catastrophe, the grey goo scenario, and weapons of mass destruction.