The difficulties associated with protein crystallization is a major obstacle in modern structural biology. The increasing demand from the protein crystal structure community for quick and non-invasive experimental techniques as well as the rapid progress of modern optics and electronics have led during the past decade to a considerable expansion of the laser light scattering techniques. The latter are now very often employed to elucidate the aggregation kinetics of supersaturated protein solutions and the mechanism(s) underlying the early nucleation stages. The experimental verification of the nucleation processes, the prediction of the effective interaction potentials and the development of appropriate diagnostics schemes are discussed.