  We discuss star formation in the turbulent interstellar medium. We argue that
morphological appearance and dynamical evolution of the gas is primarily
determined by supersonic turbulence, and that stars form via a process we call
gravoturbulent fragmentation. Turbulence that is dominated by large-scale
shocks or is free to decay leads to an efficient, clustered, and synchronized
mode of star formation. On the other hand, when turbulence carries most of its
energy on very small scales star formation is inefficient and biased towards
single objects. The fact that Galactic molecular clouds are highly filamentary
can be explained by a combination of compressional flows and shear. Some
filaments may accumulate sufficient mass and density to become gravitationally
unstable and form stars. This is observed in the Taurus molecular cloud.
Timescales and spatial distribution of protostars are well explained by the
linear theory of gravitational fragmentation of filaments. The dynamical
evolution, especially at late times, and the final mass distribution strongly
depend on the global properties of the turbulence. In dense embedded clusters
mutual protostellar interactions and competition for the available mass
reservoir lead to considerable stochastic variations between the mass growth
histories of individual stars.
