Abstract: Quantum systems with short-range interactions at sufficiently low energy are characterized by a wavelength so large that the fine details of the interactions become irrelevant and most of their properties can be effectively described by few parameters. These properties are referred to as universal as they are common to a huge variety of systems independently of their microscopic details. I will give a short overview of my research interests in few and many particle systems sharing the interest for the emergence of universal features. I will then focus on my contributions in the study of equilibrium properties of dilute Bose gases.