  Magnetic fields are important at every scale in the star formation process:
from the dynamics of the ISM in galaxies, to the collapse of turbulent
molecular clouds to form stars and in the fragmentation of individual star
forming cores. The recent development of a robust algorithm for MHD in the
Smoothed Particle Hydrodynamics method has enabled us to perform simulations of
star formation including magnetic fields at each of these scales. This paper
focusses on three questions in particular: What is the effect of magnetic
fields on fragmentation in star forming cores? How do magnetic fields affect
the collapse of turbulent molecular clouds to form stars? and: What effect do
magnetic fields have on the dynamics of the interstellar medium?
