The question how alcohol alters mood states and why this may end up becoming an addiction is puzzling alcohol researchers since decades. In this volume, an assembly of highly distinguished experts and leaders in alcohol addiction research provides lucid presentations of the current knowledge and research challenges as well as interesting viewpoints on future research directions aimed to stimulate communication and convergence between clinical and preclinical researchers, and to renew interest in the vibrant field of alcohol addiction research among a wide scientifically minded audience.