This document discusses various technologies that enable more natural user interfaces. It describes early technologies like Videoplace from the 1970s that used cameras to track body movement. More recent technologies mentioned include mobile devices that use GPS, compasses and cameras for augmented reality; hand and finger tracking using Leap Motion; and virtual and augmented reality headsets like Oculus Rift, Google Glass, and Meta. The document outlines the goal of natural interfaces as allowing interaction that comes naturally while using technology and creating interfaces that themselves feel natural.