  The evolution of User Interfaces marks a significant transition from
traditional command-line interfaces to more intuitive graphical and touch-based
interfaces, largely driven by the emergence of personal computing devices. The
advent of spatial computing and Extended Reality technologies further pushes
the boundaries, promising a fusion of physical and digital realms through
interactive environments. This paper delves into the progression from All
Realities technologies encompassing Augmented Reality, Virtual Reality, and
Mediated Reality to spatial computing, highlighting their conceptual
differences and applications. We explore enabling technologies such as
Artificial Intelligence, the Internet of Things, 5G, cloud and edge computing,
and blockchain that underpin the development of spatial computing. We further
scrutinize the initial forays into commercial spatial computing devices, with a
focus on Apple's Vision Pro, evaluating its technological advancements
alongside the challenges it faces. Through this examination, we aim to provide
insights into the potential of spatial computing to revolutionize our
interaction with digital information and the physical world.
