  This review on dark energy is intended for a wider audience, beginners as
well as experts. It contains important notes on various aspects of dark energy
and its alternatives. The section on Newtonian cosmology followed by heuristic
arguments to capture the pressure effects allows us to discuss the basic
features of physics of cosmic acceleration without actually resorting to the
framework of general theory of relativity. The brief discussion on
observational aspects of dark energy is followed by a detailed exposition of
underlying features of scalar field dynamic relevant to cosmology. The review
includes pedagogical presentation of generic features of models of dark energy
and its possible alternatives.
