  The finding of a Type Ic supernova connected with GRB 030329 showed a massive
star origin for this burst, supporting evidence for this association in
previous bursts with lightcurve bumps at the appropriate time for a supernova.
Here, we explore the possibility that all long bursts have massive star
progenitors, interacting with either the freely expanding wind of the
progenitor or the shocked wind. We present models for the afterglows of GRB
020405 and GRB 021211, which are a challenge to wind interaction models.
Considering sources for which wind interaction models are acceptable, a range
of wind densities is required, from values typical of Galactic Wolf-Rayet stars
to values ~100 times smaller. The reason for the low densities is unclear, but
may involve low progenitor masses and/or low metallicities. If mass is a
factor, a low density event should be associated with a low mass supernova. The
interpretation of bursts apparently interacting with constant density media as
interaction with a shocked wind requires both a range of mass loss densities
and a range of external pressures. The highest pressures, p/k > 10^8 cm^{-3} K,
may be due to an extreme starburst environment, which would imply that the
burst is superposed on an active star forming region. Although the range of
observed events can be accomodated by the shocked wind theory, special
circumstances are necessary to bring this about. Finally, we consider the high
velocity, high ionization absorption features observed in some afterglow
spectra. If the features are circumstellar, the presence of the burst in a
starburst region may be important for the formation of clumps near the burst.
