Are We Entering the Nano Era?

Nanotechnology has become ubiquitous in our everyday lives, from medicine and information storage to sunscreens and cosmetics. With so many applications, its risks also need to be considered. This issue, which starts with an Editorial by Y. Xia on page 12268, gives an overview of the most recent developments and challenges of nanotechnology. It contains five Reviews on current topics including nanosafety research, nanoparticles in the environment, inorganic nanoparticles, soot nanoparticles, and nanoparticles for drug delivery, as well as Communications that cover the whole spectrum of nanotechnology, from fundamental studies to catalysis, energy, and materials research.