Gamma-ray bursts (GRBs) are short and intense pulses of gamma -rays arriving from random directions in the sky and represent the most luminous electromagnetic explosions in the universe. They produce long-lived emission across the electromagnetic spectrum, from the X-ray band through optical to radio wavelengths. They are also potential emission sources of ultra-high energy cosmic rays, high-energy neutrinos, and gravitational waves. As stellar scale events located at cosmological distances, GRBs allow us to study the interstellar, galactic, and intergalactic medium as well as the first stars population and cosmology. I give here a short and partial report of our current understanding of GRBs and discuss the impact of the next generation of gamma-ray satellites AGILE and GLAST on GRBs science.