  We will describe here the structure of singularity forming in gravitational
collapse of spherically symmetric inhomogeneous dust. Such a collapse is
described by the Tolman-Bondi-Lema{\^i}tre metric. The main new result here
relates, in a general way, the formation of black holes and naked
shell-focusing singularities resulting as the final fate of such a collapse to
the generic form of regular initial data. Such a data is characterized in terms
of the density and velocity profiles of the matter, specified on an initial
time slice from which the collapse commences. We show that given any generic
density profile at the initial time slice, there exists a corresponding
velocity profile which gives rise to a strong curvature naked singularity. This
establishes that strong naked singularities arise for a generic density
profile. We also establish here that similar results hold for black hole
formation as well. Keeping the model to be spherically symmetric we also
consider more general form of matter fields, i.e. equation of state $p =
k\rho$. We will analyse here the nature of non-central singularity forming due
to collapse of spherically symmetric perfect fluid subject to weak energy
condition.
