Despite its undeniable influence upon their daily lives, Operational Research (OR) is an academic discipline most members of the general public and indeed many academics in other disciplines have never heard of before. This is in no small part due to the striking absence of a clear definition or even an agreed upon name among the scientists working within it (Management Science, anyone?). Defining a discipline as varied as OR is no easy task however, especially when one considers the speed with which it has matured in recent decades and how it now stands strong as a truly interdisciplinary field: an exciting melting pot for theories and methodologies from mathematics, management, computer science, economics, engineering, decision support, soft computing and many more. Throughout the 29th European Conference of Operational Research which took place in Valencia July 8-13th earlier this year, we also witnessed how our discipline is increasingly extending its reach into additional fields such as psychology, knowledge management, education, quality management and even ergonomics. Not only have these movements bolstered the influence of OR, but they have also begun to destabilize the monopoly profit-driven objectives and goals once held. The programme for EURO 2018 is in itself evidence for this seismic shift, with the aspirations of many of the abstracts therein aligned with humanitarianism, improved living and working conditions, sustainability, safety and fairness. Re-evaluation and diversification of such objectives means that OR is a ubiquitous science whose ubiquity will only intensify further in the coming years. This special issue therefore seeks to collect the finest and highest quality examples and original contributions of research and methodologies with potentially far-reaching impacts upon the field, either with respect to its core tools and problems or at the far reaches of our rich and complex discipline.