  The piling up of a macroscopic fraction of noninteracting bosons in the
lowest energy state of a system at very low temperatures is known as
Bose-Einstein condensation. It took nearly 70 years to observe the condensate
after their theoretical prediction. A brief history of the relevant
developments, essentials of the basic theory, physics of the steps involved in
producing the condensate in a gas of alkali atoms together with the pertinent
theory, and some important features of the research work carried out in the
last about 25 years have been dealt with. An effort has been made to present
the material in a manner that it can be easily followed by undergraduate
students as well as non-specialists and may even be used for classroom
teaching.
