Physics of Quantum Fluids : New Trends and Hot Topics in Atomic and Polariton Condensates The study of quantum fluids stimulated by the discovery of superfluidity in liquid helium has experienced renewed interest after the observation of Bose Einstein condensation (BEC) in ultra cold atomic gases and the observation a new type of quantum fluid with specific characteristics derived from its intrinsic out of equilibrium nature. The main objective of this book is to take a snapshot of the state of the art of this fast moving field with a special emphasis on the hot topics and new trends. Bringing together the most active specialists of the two areas (atomic and polaritonic quantum fluids) we expect that this book will facilitate the exchange and the collaboration between these two communities working on subjects with very strong analogies