In this issue:
"Why We Help": Cooperation has been one of the driving forces of evolution.
"Secrets of the HIV Controllers": A rare group of HIV-positive individuals' good fortune could point the way to more powerful treatments - and perhaps a vaccine.
"Witness to an Antarctic Meltdown": Scientists are racing to Antarctica in an effort to find out how fast glaciers are melting and what this could mean for rising sea-levels.
"Machines That Think for Themselves": New techniques that teach computers to learn - and beat the experts.
©2012 Scientific American