  Gamma-ray bursts (GRBs) are extremely energetic events at cosmological
distances. They provide unique laboratory to investigate fundamental physical
processes under extreme conditions. Due to extreme luminosities, GRBs are
detectable at very high redshifts and potential tracers of cosmic star
formation rate at early epoch. While the launch of {\it Swift} and {\it Fermi}
has increased our understanding of GRBs tremendously, many new questions have
opened up. Radio observations of GRBs uniquely probe the energetics and
environments of the explosion. However, currently only 30\% of the bursts are
detected in radio bands. Radio observations with upcoming sensitive telescopes
will potentially increase the sample size significantly, and allow one to
follow the individual bursts for a much longer duration and be able to answer
some of the important issues related to true calorimetry, reverse shock
emission and environments around the massive stars exploding as GRBs in the
early Universe.
