"Exoplanet Properties in Light of Their Stars and Their Stellar Companions" // A majority of exoplanets known today have been found with the transit method. The Kepler Space Telescope has found over 4000 planet candidates, among them many Earth-sized planets. However, the size of the planets derived from transits depends on the size of the star. A stellar companion will dilute the transit signal and lead to planet radii that are underestimated. In this talk I will present results from the Kepler imaging follow-up program, which was aimed at finding stellar companions to Kepler planet host stars. The detected companions allow us to derive a planet radius correction factor for each star and therefore corrected radii for the planets orbiting it. I will also show how the presence of companions not only alters the derived planet radii, but also the bulk densities and thus composition of the planets, leading to planets that are more volatile-rich.