Visibility of spacetime singularities formed in the gravitational collapse of a star has been one of the most disputed topics of modern astrophysics and cosmology for the past four decades. This provocative, topical book presents the scientific foundation for thinking that spacetime singularities formed in the collapse of a star might be visible. The book portrays methods for determining the nature of singularities arising in four and higher dimensional spacetimes. It is the most comprehensive book, which will be an essential reading for astrophysicists, cosmologists and all those interested in understanding the gravitational collapse of a star.