Muggles' Guide to Harry Potter/Magic/Pureblood

Overview
A Pureblood is a witch or wizard who descends from other witches and wizards only (not Muggles).

Extended Description
The followers (most commonly know as Death eaters)of Lord Voldemort believe that there is a distinction between those who are descended entirely from those who are able to do magic and those who have non-magical blood in their ancestry. Echoing the views of Salazar Slytherin, one of the founders of Hogwarts, Voldemort believes that non-magical ancestry somehow taints the bloodline. Only those with no such taint deserve to be called Pureblood, and only Purebloods deserve to be taught magic.

It is perhaps interesting that Voldemort himself is not a pureblood; while his mother, Merope Gaunt, was a member of one of the oldest Wizarding familes in existence, his hated father was a “Muggle”. In spite of this, he is still considered the heir of Salazar Slytherin.

The term Pureblood first appears in Harry Potter and the Chamber of Secrets, but Draco's hatred of Hermione clearly stems from this prejudice, and is evident from the beginning of the series.

Analysis
The idea of "racial purity" pervades the entire series. While the core story is Voldemort's return to power, and Harry's battle to prevent this, it is necessary for Voldemort's followers to break Wizarding law in order to restore him to power. The only way that they can justify this to themselves is to demonize the main Wizarding community, as being somehow sub-Wizard because of their Muggle ancestry. This is quite sharply brought out in the episode with the Gaunt family, as viewed in Dumbledore's Pensieve in Harry Potter and the Half-Blood Prince. The Gaunt family would apparently rather live in solitude and squalor with their pride in being pure-bloods, than join the Wizarding community and accept the fact that their status was no higher than that of Wizards who had Muggle parents.

It has been mentioned in the discussion of Lord Voldemort that this emphasis on racial purity is very similar to the German Nazi ideas of pure Aryan heritage – and there is an interesting parallel in that Hitler himself was not pure Aryan.

It is also mentioned, in the topic Half-blood, that in fact many half-bloods, including Lord Voldemort himself, are more powerful magicians than many Purebloods.

Greater Picture
There are a number of parallels between the earlier Dark period when Grindelwald was in power, and the Second World War; the author seems to have put the decisive battle with Grindelwald in 1945, and then imprisoned him alone in Nurmengard, a jail that he had constructed for his enemies, in an obvious nod to Rudolf Hess' imprisonment alone in Spandau Prison. The author has also remarked on an amazing similarity between the events in the Wizarding world between Fudge's denial of Voldemort's return, and the appearance of Voldemort before witnesses in the Ministry a year later, and the events in England under Chamberlain while the Third Reich was consolidating its power base. While the latter was apparently accidental, the former was not; and so we should not be surprised by similarities between Hitler's Final Solution and Voldemort's. One wonders if there is some Muggle philosopher who preached extinction of the unfit that Hitler was using as his role model, the way Voldemort (and, one supposes, Grindelwald) were basing their campaigns on Salazar Slytherin.