"Cosmology has seen the growth of an enthusiastic interest in the Dark Universe we live in. Observations show that ordinary matter is only a small fraction of the total energy in the Universe. The rest is in the form of Dark Matter and Dark Energy. They both emit no light: Dark Matter feels gravitational attraction and allows galaxies to form; Dark Energy contrasts gravity and makes the Universe expand faster and faster.My research project will identify the observable effects that indicate dynamics in the Dark Energy component, disentangling it from a cosmological constant. To do this I will investigate interactions among Dark Energy and other species in the Universe. Furthermore, I will consider the case in which General Relativity itself is modified.I will predict effects on cosmic microwave background and structure formation. Halo profiles, supercluster structures, the Integrated Sachs-Wolfe effect are some of the features affected by an interaction that can make Dark Energy dynamics observable.I will compare my findings to experiments like PLANCK and EUCLID. The PLANCK satellite is now observing the cosmic microwave background with precision higher than ever. As part of the PLANCK collaboration, I can analyze the data and extract from them information on cosmology and Dark Energy. EUCLID has reached the final selection stages of the ESA Cosmic Vision Program: its proposal is based on a satellite which will observe galaxies at distances higher than ever. I will forecast the ability of EUCLID to investigate Dark Energy and modified gravity through effects on structure formation.The research in Geneva will allow me to investigate the impact of the Large Hadron Collider findings right at the time when LHC results will be made available.The discovery of an interaction would be inestimable for cosmology, providing a specific tool to disentangle dynamical dark energy from a cosmological constant, with a profound impact on our knowledge of the universe."