  Observational advances over the last decade reveal that star formation is
associated with the simultaneous presence of gravitationally collapsing gas,
bipolar outflow, and an accretion disk. Two theoretical views of star formation
suppose that either stellar mass is determined from the outset by gravitational
instability, or by the outflow which sweeps away the collapsing envelope of
initially singular density distributions. Neither picture appears to explain
all of the facts. This contribution examines some of the key issues facing star
formation theory.
