There are many different kinds of werewolves, and the Alpha Wolf is just one. Although some may argue the Alpha Wolf is the most important and powerful kind of werewolf there is.
Historically the Alpha werewolf is a shape changing creature that can become wolf by rubbing an ointment on themselves or by wearing a charm. Other ancient legends point to heredity playing a big part in the Alpha wolves. These legends state that one can only be an Alpha wolf if they are born into it. The legend also states that it can sometimes skip a generation, leaving some members of the family in complete unchanging human form. Should a new generation have the Alpha wolf gene passed onto them, it usually does not show up until puberty. Those who become Alpha wolves this way are thought to have supernatural strength and even some psychic abilities.
Ancient legend also states that there is one way to become an Alpha wolf without being born into the family line. That exception is to make a pact with the devil but this was a most extreme method. It was thought to only occur when a human wanted to seek revenge upon the death of someone they loved. Being in Alpha form could then give them supernatural abilities to conquer anyone and anything. Should one become an Alpha wolf this way, it’s thought that the shape-changing can be done at the wolf’s will and no conditions, such as a full moon, are needed.
The Twilight series focuses heavily on the Alpha wolf, with Jacob Black as the rightful heir to the title. In this take on the myth, Jacob gives up this right to another in the pack, Sam, and becomes Sam’s right-hand companion. Twilight has a very interest take on the Alpha role position and it continues to come up throughout the entire series.