  The cosmological model best capable of fitting current observational data
features two separate epochs during which the Universe is accelerating. During
the earliest stages of the Universe, such acceleration is known as cosmological
inflation, believed to explain the global properties of the Universe and the
origin of structure. Observations of the present state of the Universe strongly
suggest that its density is currently dominated by dark energy with properties
equivalent or similar to a cosmological constant. In these lecture notes, I
provide an introductory account of both topics, including the possibility that
the two epochs may share the same physical description, and give an overview of
the current status.
