  We investigate the dynamics of the recently proposed model of assisted
inflation. In this model an arbitrary number of scalar fields with exponential
potentials evolve towards an inflationary scaling solution, even if each of the
individual potentials is too steep to support inflation on its own. By choosing
an appropriate rotation in field space we can write down explicitly the
potential for the weighted mean field along the scaling solution and for fields
orthogonal to it. This demonstrates that the potential has a global minimum
along the scaling solution. We show that the potential close to this attractor
in the rotated field space is analogous to a hybrid inflation model, but with
the vacuum energy having an exponential dependence upon a dilaton field. We
present analytic solutions describing homogeneous and inhomogeneous
perturbations about the attractor solution without resorting to slow-roll
approximations. We discuss the curvature and isocurvature perturbation spectra
produced from vacuum fluctuations during assisted inflation.
