Dogmeat is a player companion in the Fallout series. He gained his name from the post-apocalyptic movie, 'A Boy and His Dog'. The dog in the movie the accompanies the protagonist, is called Blood, but at one point, the boy refers to him as Dogmeat.
Dogmeat also makes another reference to a movie, Mad Max, which Max has an Australian Cattle dog. This is the same breed that Dogmeat is.
Dogmeat will join you in the first two games regardless of Karma.
Dogmeat can be located in the town of Junktown. He blocks the entrance of a home and the owner asks you to deal with it. If the player wears a leather jacket or feeds Dogmeat, he will join your party.
It is considered canon that Dogmeat died in the force fields of the Military base.
Dogmeat can be recruited only after a special encounter at the Cafe of Broken Dreams. Dogmeat will join your party if the player is not wearing any armor.