| Abstract: I will discuss our present knowledge of the statistics of stellar multiplicity (the multiplicity fraction and the distribution of periods, mass ratios, and eccentricities), and the implications for stellar evolution, in particular for Type Ia Supernovae (SN Ia). I will describe how multi-epoch radial velocity measurements from large spectroscopic surveys can open a new observational window on stellar multiplicity, and present two case studies: white dwarfs in SDSS/SEGUE, and red giants in SDSS/APOGEE. For the white dwarfs, we can measure their merger rate and evaluate their viability as Type Ia SN progenitors. For the red giants, we can explore the interplay between stellar evolution and stellar multiplicity, evaluate the rate of stellar mergers, and uncover a strong metallicity dependence of the multiplicity fraction. I will also describe how the APOGEE analysis led to the dicovery of the first non-interacting stellar mass black hole. |