Quantum computers promise to unlock a computational power beyond the reach of classical platforms. In this context, photonic Boson Sampling is believed to provide a strong evidence of such quantum speedup already with forthcoming technologies. However, in the regime where Boson Sampling devices start surpassing classical computers, it becomes fundamental to develop efficient and reliable techniques to validate their quantum operation. In this work we describe in a unified framework the accomplishments achieved in the scope of Boson Sampling, with a particular focus on its implementation and validation on integrated photonic platforms. The results consolidate the general belief that such devices are indeed capable to provide reliable demonstrations of quantum supremacy.