Over the last few decades there have been profound changes in understanding how volcanoes work. Some of the factors that have enabled advances in volcanology have been technologically driven, with introduction of novel instrumentation and prodigious increases in computer power and speed. The quality and quantity of data on volcanic eruptions and their products has increased dramatically as have the sophistication of mathematic modelling. This era has seen the development of dynamical models of volcanic processes based on chemical and physical principles combined with measurements of key physical properties, such as magma viscosity. Experimental research has also allowed models to be tested and has enabled investigation of processes inaccessible to direct observations, such as explosive flows in volcanic conduits. A small number of erupting volcanoes have been documented in great detail, such as Mount St Helens and Soufrière Hills Volcano, Montserrat, and have had a major influence on progress as natural laboratories to test models, to identify new phenomena and to inform the development of conceptual and mathematical models of volcanism. The scientific environment of a major eruption has promoted multidisciplinary research teams and collaborations, provided the opportunity to collect huge amounts of different kinds of data and facilitated the integration of major relevant disciplines such as applied mathematics, statistics, atmospheric sciences, experimental volcanology, seismology, instrument engineering, remote sensing, geodesy, geochemistry and petrology. In this lecture I will highlight some emerging new concepts, including the understanding of controls on time scales of episodic volcanism, the dispersal of volcanic ash, the nature of magma reservoirs, the role of magmatic fluids in driving volcanism and the formation of porphyry copper deposits.