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Accretion is one of the key processes in astrophysics, controlling
everything from the feeding of supermassive black holes to the formation of
stars. And building stars involves the collapse and fragmentation of molecular
clouds and the formation and evolution of discs which can form planets. The
subject is complex, but Lee Hartmann provides an admirable overview of our
current understanding in Accretion Processes in Star Formation. Published by
Cambridge University Press, £45, ISBN 0521435072.