Tribology is the study of phenomena that occur at contacting and sliding interfaces. It is a very relevant field, given the global impact of tribology in terms of energy efficiency and material waste. However, it is also scientifically fascinating because of the complexity of the physical phenomena that occur at interfaces. For example, a lubricated sliding contact involves deformation of solids, fluid flow, rheology, chemical reactions, and much more. This necessarily means that a comprehensive understanding of tribological phenomena requires knowledge from a range of classical fields in science and engineering, including chemistry, physics, mechanical engineering, and materials science. Most tribologists are experts in one of these areas based on their academic training and then learn enough about the others to communicate effectively. However, the next significant breakthroughs in tribology are likely to be found at the interfaces between the classical fields. To achieve these breakthroughs, the very diverse tribology community needs to come together to learn and discover together. This is the focus of the 2018 Gordon Research Conference on Tribology: cutting-edge interface research that is happening at the interface between disciplines.