One great challenge of nanotechnology concerns the design and synthesis of multi-component nanoparticles that beat the properties of their elemental counterparts. Cluster beam deposition (CBD)provides a solvent-free and effluent-free method to achieve nanomaterials with tailored characteristics. However, CBD is hindered by low cluster yield and, often, by limited structural control. In gas-phase methods one cannot inhibit or enhance growth by adding or removing chemical precursors or surfactants; cluster formation happens in-flight, and the only viable strategy for superior control is by understanding the kinetics and thermodynamics of nucleation and growth. To this end, atomistic computer modelling is an invaluable tool, complementing experimental fabrication, as demonstrated by numerous case studies based on various setups of CBD sources.