Neutrino mass and mixing are amongst the major discoveries of recent years. From the observation of neutrino flavor change in solar and atmospheric neutrino experiments to the measurements of neutrino mixing with terrestrial neutrinos, recent experiments have revealed new particle properties of neutrinos and provided the first hint of physics beyond the Standard Model of particle physics. These observations have helped solve the long-standing Solar Neutrino Problem, the apparent deficit of the observed electron solar neutrino flux, and have contributed to a better understanding of the role of neutrinos in the Universe. A broad field of neutrino research has emerged in particle, nuclear, and astrophysics. The observed phenomenon of neutrino oscillation not only requires an extension of the Standard Model but may hold the key to understanding the observed baryon asymmetry in the Universe. With emphasis on my research in solar and reactor neutrino physics I will review the recent discoveries in neutrino physics, describe the evidence for the mixing of massive neutrinos, and discuss its implications for neutrino astrophysics and cosmology. I will conclude with a summary of the outstanding questions in neutrino particle and astrophysics.