Making accretion disks around black holes: GRB progenitors

We review the current progenitors of the rapidly accreting black holes which are thought to power gamma-ray bursts. Differences in the evolutionary scenarios of these progenitors lead to differences in the observed properties of the bursts (e.g., burst duration, burst location, and afterglow emission). We pay particular attention to the differences between helium merger and collapsar gamma-ray burst progenitors (the two leading progenitors for long-duration gamma-ray bursts).