The astronomer to first discover a galaxy was Persian al-Sufi. He discovered the galaxy Andromeda, which along with the milky way, is one of the largest known galaxies.  Yet, research in galaxies was rather slow, and only three had been discovered by the 18th century.  Then in 1780, a French astronomer named Charles Messier published a list of 32 galaxies, and thus the term Messier(M) comes from.   Stars are not given individual names because there are too many of them.  So instead they are named Messier and a number, example: Andromeda is M31.  

In 1912, Edwin Hubble announced that the galaxies are moving away from each other, and this means that the universe is still expanding.  No on knows whether it will continue to expand, or if there is enough material for it to expand further. 

Galaxies come in four shapes: globular, elliptical, spiral, and irregular. Globular has definite shape, and has a bright nucleaus.  Elliptical contains old stars with very littled gas or dust, yet they can be from dwarf size to giant size.   Spiral shape are flattened disks with old and new stars, gas, dust, and molecular clouds(these are probably the most dramatic).  Irregulars are those that have a dislike shape, but are not spiral, and they are usually located near larger galaxies.   Galaxies are generally not isolated, but together in groups.  Earths galaxy is one of 20 in a group called the Local Group. The Local Group is located on the outside of the nearest cluster, Virgo.  All within the cluster have the same movement, which could mean there is a supercluster near that has not been found yet.  Superclusters are arranged in long, string-like lacy filaments.  The most famous is the Great Wall, a filament discovered in 1989 that is a half billion light years long.