  In recent years, Loop Quantum Gravity has emerged as a solid candidate for a
nonperturbative quantum theory of General Relativity. It is a background
independent theory based on a description of the gravitational field in terms
of holonomies and fluxes. In order to discuss its physical implications, a lot
of attention has been paid to the application of the quantization techniques of
Loop Quantum Gravity to symmetry reduced models with cosmological solutions, a
line of research that has been called Loop Quantum Cosmology. We summarize its
fundamentals and the main differences with respect to the more conventional
quantization approaches employed in cosmology until now. In addition, we
comment on the most important results that have been obtained in Loop Quantum
Cosmology by analyzing simple homogeneous and isotropic models. These results
include the resolution of the classical big-bang singularity, which is replaced
by a quantum bounce.
