Optimization: this beguilingly simply idea allows biologists not only to understand current adaptations, but also to predict new designs that may yet evolve.

For years, cosmologists have been racing each other to develop ever more sophisticated and realistic models of the evolution of the Universe. The competition has just become considerably stiffer.

The ability to control charge transport through individual molecules sandwiched between electrodes could lead to further miniaturization of electronics. A better understanding of how such junctions work is crucial.