Abstract:The Benjamin-Ono equation is a PDE from Fluid Mechanics, introduced in 1967.For more than fifty years, it has focused many research works from mathematicians and physicists, probably because it combines two features : on the one hand, it is a nonlinear Hamiltonian PDE with a non local term. On the other hand, it admits a special structure which allows it to be considered as an integrable PDE. I will try to explain in which sense this equation is integrable, and to describe the expected role played in its long time dynamics by special solutions called the solitons.