Gamma-ray bursts (GRBs) are intense, short bursts of high-energy gamma rays, first discovered in the 1960s by the Vela satellites. The BATSE detector on the COMPTON-GRO satellite revolutionized GRB observations, showing they originate at cosmological distances. BeppoSAX confirmed this by detecting X-ray afterglows and redshifted absorption lines in GRB970508, confirming their extragalactic origin. GRBs release $ \sim10^{51}-10^{53} $ ergs in seconds, making them the most luminous objects in the universe. The "fireball" model explains GRBs as the conversion of ultra-relativistic particle or electromagnetic energy to radiation in an optically thin region. The "inner engine" driving this process is hidden, but its activity is reflected in the complex temporal structure of GRBs, suggesting it is associated with a compact object like a black hole. GRBs are rare, with one burst per million years per galaxy. Their origin remains mysterious, unlike other astronomical phenomena, due to their transient nature and lack of known counterparts. The fireball model, supported by afterglow observations, suggests GRBs result from internal shocks in a relativistic jet. The "inner engine" is likely a compact object, and the observed temporal structure indicates its activity. GRBs are associated with star-forming regions, and their host galaxies are often faint and distant. The discovery of afterglows has allowed accurate identification of host galaxies, confirming their cosmological origin. GRBs have implications for cosmology, including studying dark matter and the large-scale structure of the universe. The distribution of GRBs is isotropic, supporting their extragalactic origin. The "no host" problem has been resolved with afterglow observations, showing GRBs are associated with star-forming galaxies. The fireball model remains the leading explanation, with ongoing research into their origins and implications.Gamma-ray bursts (GRBs) are intense, short bursts of high-energy gamma rays, first discovered in the 1960s by the Vela satellites. The BATSE detector on the COMPTON-GRO satellite revolutionized GRB observations, showing they originate at cosmological distances. BeppoSAX confirmed this by detecting X-ray afterglows and redshifted absorption lines in GRB970508, confirming their extragalactic origin. GRBs release $ \sim10^{51}-10^{53} $ ergs in seconds, making them the most luminous objects in the universe. The "fireball" model explains GRBs as the conversion of ultra-relativistic particle or electromagnetic energy to radiation in an optically thin region. The "inner engine" driving this process is hidden, but its activity is reflected in the complex temporal structure of GRBs, suggesting it is associated with a compact object like a black hole. GRBs are rare, with one burst per million years per galaxy. Their origin remains mysterious, unlike other astronomical phenomena, due to their transient nature and lack of known counterparts. The fireball model, supported by afterglow observations, suggests GRBs result from internal shocks in a relativistic jet. The "inner engine" is likely a compact object, and the observed temporal structure indicates its activity. GRBs are associated with star-forming regions, and their host galaxies are often faint and distant. The discovery of afterglows has allowed accurate identification of host galaxies, confirming their cosmological origin. GRBs have implications for cosmology, including studying dark matter and the large-scale structure of the universe. The distribution of GRBs is isotropic, supporting their extragalactic origin. The "no host" problem has been resolved with afterglow observations, showing GRBs are associated with star-forming galaxies. The fireball model remains the leading explanation, with ongoing research into their origins and implications.