purposes ceased for an object in stasis, no harm can come to anything within the field. The idea that luck is a genetic trait that can be strengthened by selective breeding. The tasp, a device that remotely stimulates the pleasure center of the brain; it temporarily incapacitates its target and is extremely psychologically addictive. If the subject cannot, for whatever reason, get access to the device, intense depression can result, often to the point of madness or suicide. To use a tasp on someone from hiding, relieving them of their anger or depression, is called "making their day". Boosterspice, a drug that restores or indefinitely preserves youth. Scrith, the metal-like substance of which the Ringworld is built (and presumably the shadow squares and wires too), that has a tensile strength nearly equal in magnitude to the strong nuclear force making it similar to the concept of nuclear matter. This makes it an example of unobtainium. This is similar to the Pak Protector's "twing" used in other Larry Niven stories. Impact armor, a flexible form of clothing that hardens instantly into a rigid form stronger than steel when rapidly deformed, similar to certain types of bulletproof vests. The hyperspace shunt, an engine for faster-than-light travel, but slow enough (1 light-year per 3 days, ~122 c) to keep the galaxy vast and unknown; the new "quantum II hyperspace shunt", developed by the Puppeteers but not yet released to humans, can cross a light-year in just 1.25 minutes (~421 000 c). Point-to-point teleportation at the speed of light is possible with transfer booths (on Earth) and stepping disks (on the Puppeteer homeworld); on Earth, people's sense of place and global position has been lost due to instantaneous travel; cities and cultures have blended together. A theme well covered in the novel is that of cultures suffering technological breakdowns who then proceed to revert to belief systems along religious lines. Most Ringworld societies have forgotten that they live on an artificial structure, and now attribute the phenomena and origin of their world to divine power. Errors The opening chapter of the original paperback edition of Ringworld featured Louis Wu teleporting eastward around the Earth in order to extend his birthday. Moving in this direction would, in fact, make local time later rather than earlier, so that Wu would soon arrive in the early morning of the next calendar day. Niven was "endlessly teased" about