Solid-liquid interfaces are ubiquitous, and understanding how dynamic processes take place there, with molecular resolution, is important to many fields. In this article we first give an overview of the most important theories including charging processes and the electric double layer. Next we consider the characteristics that describe the interface at the molecular scale. Finally we focus on various processes in the three main categories of adsorption, transport and redox processes that occur at interfaces and how they are investigated using simulations and experimental techniques with molecular resolution. We highlight the ways these processes relate to tackling current global challenges.