Many of us have watched a fly perform a flawless landing on the rim of a teacup, or observed a honeybee seek and locate a new source of food several kilometers away from its hive and return home unerringly, or marveled at a bird flying rapidly through dense foliage without touching a single branch. Flying insects and birds are surprisingly competent at moving and navigating in their environment, despite the fact that they possess brains that are very much smaller than our own and which carry far fewer neurons. Evidently these creatures are using vision sensors and principles of information processing and guidance that are not only effective, but also computationally simple.