| Exoplanet science was jump-started in the 1990s by the first radial velocity (RV) or "Doppler wobble" measurements of an extra-solar planet's gravitational effect on its host star. Since then, the most productive means of finding new exoplanets has moved from the radial velocity method to the transit method, in which a planet passes in front of its host star and we measure from Earth the small decrease in the star's brightness. However, going beyond "butterfly collecting" to better understand exoplanet demographics necessitates RV observations to measure the bulk compositions of transiting exoplanets, as well as explore parameter spaces that are not typically covered by the transit method. In this talk I will describe what we are learning today from RV studies of exoplanets, the current limitations to these studies and how we (think we) can overcome them, and how future RV studies will help us understand whether our Solar System is rare in the Galaxy or not. |