"It is a long held dream of chemical physicists to study (and ultimately control!) the interactions between individual molecules in completely specified collisions. This project brings this goal within reach. I will develop a novel crossed molecular beam scattering apparatus in which precise control over the molecules prior to the collision is obtained, and in which the scattering products are detected with the highest possible resolution. The velocity and quantum state of molecules is brought fully under control using Stark and Zeeman decelerators. The angular and velocity distributions of the scattering products will be probed using velocity map imaging. The monochromatic molecular beam pulses afforded by the Stark and Zeeman decelerators will yield scattering images with unprecedented sharpness, adding a new dimension to the information that can be extracted from the measured differential cross sections. This “best of both worlds” combination allows for bimolecular scattering studies at unexplored energies and with unprecedented resolution. I will exploit these new possibilities to study scattering phenomena that provide insights in molecular scattering mechanisms that were previously beyond the realm of experimentalists. These include quantum tunneling phenomena and scattering resonances in low-energy collisions, rotational product-pair correlations in bimolecular collisions, and non-adiabatic effects in the multi-surface dynamics beyond the Born-Oppenheimer approximation for radical-radical collisions. The scattering data that will be obtained will challenge the most sophisticated theoretical models to calculate molecular potential energy surfaces to date, and will foster major steps forward in our understanding of molecular interactions. The approach proposed here will open up a new and intellectually rich research field in chemical physics, and will comprise a major breakthrough in the upcoming research field of cold molecules."