Recent observations of the Hubble Deep Field (Abraham et al., 1996) have
shown that the fraction of peculiar objects seen is
significantly higher than it is among nearby galaxies. A sizable
fraction of QSO hosts appear to be ongoing mergers, as originally envisioned. On a more fundamental level, mergers are thought to play an
important role in structure formation in the early matter dominated epoch of the Universe.
However, mergers are not confined to exotic circumstances in history;
if we look at the local Universe, there
are numerous examples of disturbed galaxies that quite obviously point to galaxy interactions. Such a view was not always held; for
many years, right up until the early 1970's, many held the opinion
that simple gravity acting on stars could not produce the
characteristic
features - bridges and tails being the prime examples - of the
class of peculiar galaxies.