  We analyze pulse properties of Short gamma-ray bursts (GRBs) from a new
catalog containing 434 pulses from 387 BATSE Time-Tagged Event (TTE) GRBs.
Short GRB pulses exhibit correlated properties of duration, fluence, hardness,
and amplitude, and they evolve hard-to-soft while undergoing similar
triple-peaked light curves similar to those found in Long/Intermediate bursts.
We classify pulse light curves using their temporal complexities, demonstrating
that Short GRB pulses exhibit a range of complexities from smooth to highly
variable. Most of the bright, hard, chaotic emission seen in complex pulses
seems to represent a separate highly-variable emission component. Unlike
Long/Intermediate bursts, as many as 90\% of Short GRBs are single-pulsed.
However, emission in Short multi-pulsed bursts is coupled such that the first
pulse's duration is a predictor of both the interpulse separation and
subsequent pulse durations. These results strongly support the idea that
external shocks produce the prompt emission seen in Short GRBs. The
similarities between the triple-peaked structures and spectral evolution of
Long, Short, and Intermediate GRBs then suggests that external shocks are
responsible for the prompt emission observed in all GRB classes. In addition to
these findings, we identify a new type of gamma-ray transient in which peak
amplitudes occur at the end of the burst rather than at earlier times. Some of
these "Crescendo" bursts are preceded by rapid-fire "Staccato" pulses, whereas
the remaining are preceded by a variable episode that could be unresolved
staccato pulses.
