The environment close to a typical protostar contains gas and dust that is rotating around the star in a disc, as well as outflowing in a wind and plummeting down magnetic field lines onto the protostar itself. This gas and dust is adding to the protostar's mass, is injecting energy into the interstellar medium (perhaps inducing further star formation) and is also clumping together to form planets. Although rich in physics, this environment is on a scale that is far too small to be observed using traditional imaging, and we must turn to other methods, such as spectroscopy, polarimetry and interferometry to probe the geometry, dynamics and physical conditions of the gas.This PhD project involves using a combination of numerical modelling and observations obtained on international facilities (such as the VLT and WHT) to examine the processes that occur within a few radii of protostars, with the aim of measuring the accretion rates onto protostars and how the magnetic field interacts with the planet-forming disc.This project would be suitable for a student with an interest in both observations (particularly infrared spectroscopy and interferometry) and computer modelling.