Professor Severus Snape is one of the characters of Harry Potter. He is a teacher at Hogwarts who teaches Potions. He is also the head of Slytherin, one of the four houses at Hogwarts.

He is one of the most disliked people in the book; this being for his sadistic and sarcastic nature. He constantly picks on anyone other than Slytherin, especially Harry Potter.

He is also known, to us readers, as a dark and mysterious person. His personality is the most intriguing from the book. He keeps to himself most of the time and doesn't really like to socialise with people - unless he has to insult someone. Some readers find this rather interesting and challenging, some can even relate to him. Some just hate him.

Opinion: Something I'd like to say before we continue: Snape is not a vampire. He has pale skin because he hangs out in the dungeons - only because he has his lessons there. Where else can you teach potions and not be afraid of ruining the carpet? He may of course be a vampire, but the author, J.K Rowling, hasn't confirmed this rumour yet.

If you've come this far, kudos! Here's a cookie, you deserve it.

He enters the book as a villain. We are forced to believe he wants to kill Harry Potter and escape with the Philosopher's/Sorcerer's stone - which gives eternal life.

To most of our astonishment's, Snape is actually the one trying to save Harry. This is only because he had owed Harry's father. This fact brought Snape a lot of respect from readers. It showed that he had honour even when he loathed Harry.

In the second book, we don't learn much about Snape. Just to hate him more. We learn that he tries to humiliate and expel Harry Potter with every chance he gets. We still don't fully understand why he hates Harry, he just hates him.

The third book gets rather juicy for Snape fans. We learn a lot about his past, including his involvement with Harry's father.

We find out that Snape used to try and make Harry's father's (James Potter) life as miserable as possible. He used to follow James and his friends to try to get an excuse for their exclusion. James had three friends he had mostly hung around during school - Sirius Black, Remus Lupin and Peter Pettigrew (all four were known as The Marauders).

Sirius Black was also loathed by Snape. Of course, the feeling was mutual. Black had once played a vicious prank on Snape during their seventh year at school. He had tricked Snape in meeting a fully-formed werewolf, which were dangerous back then.

Before the confrontation could take place, James had stopped and warned Snape (hence the 'I owe you' back in book one). Despite this, Snape believed all of James' gang were in on the prank and doesn't forgive them. Through learning all this, we still don't understand why he loathed The Marauders so passionately.

In the present, Sirius Black has escaped from wizard prison (known as Azkaban). He's on the run, but at the same time trying to clear his name. He was innocent and didn't deserve to be put in prison (No, Snape had nothing to do with his imprisonment).

While this is going on, Snape finds out that Harry is breaking a school rule by being outside of Hogwart's grounds. With the glee of being able to punish Harry, Snape goes to investigate what Harry is up to. By reaching Harry's destination, he finds himself face to face with Sirius Black.

Memories of his childhood at school come flooding back, which make Snape fill with anger. He corners Black, making sure he has no chance in escaping. Snape threatens to kill him right there and then, having the upper hand in the situation, but decides to hand him in. What they do to escaped prisoners is so much worse than what Snape could do. In addition, Snape will be awarded for handing in an escaped prisoner.

Unfortunately, Snape doesn't get to hand Black in because he's knocked unconscious (thanks to Harry, who, if you remember, was in Black's presence at the time) and unable to stop him getting away. When he comes to, Snape tries to blame Harry for Black's escape, but to no avail.

Book four has a whole new twist for Snape fans. We learn more on the Dark Lord, Voldemort (the ultimate villain in the books).

Voldemort (silent 't', people) is the most feared wizard in the world. He's so feared, that even speaking his name is frightening. Voldemort was responsible for a lot of killings and crimes when he was in control. No one ever dared mess with him or get in his way. He fell (nearly killed, but outta business) when he attempted to kill Harry Potter. He was unable to kill Harry, who was then just a baby, and had somehow been defeated. That is why Harry Potter is the main character of the series. He was The Boy Who Lived and had managed to defeat the ultimate villain (yes, when he was just a baby).

While at large, Voldemort had minions to do his work for him. These were called the Death Eaters. Death Eaters were ordinary people, with ordinary lives, but worked for the Dark Lord. They were also feared when Voldemort ruled. A mark was burned onto their left forearm to identify who they were. This mark was known as the Dark Mark, and stung whenever Voldemort needed them. The Death Eaters separated after their master fell (nearly killed, but outta business).

During book four, they reunited because they believed Voldemort would rise again. They caused a little mayhem here and there to scare the wizardry world.

At Hogwarts, Snape is being agitated by a Death Eater who doesn't want to return to Voldemort if he rises. When news comes that Voldemort has finally risen, this Death Eater flees, clearly afraid of his ex-master.

Well, we soon learn that Snape himself was once a Death Eater. He was active only until he was convinced to turn spy for Albus Dumbledore (good wizard, as strong as Voldemort, also head master of Hogwarts). Basically, Snape was once a Death Eater but turned spy. His reasons for turning good are not clear, but where his loyalty lies are.

Voldemort finds out that Snape had turned spy and vows to kill him. Leaving no choices for Snape, he is forced to completely depart from the Death Eaters.

In book five, we learn of The Order of the Phoenix. Albus Dumbledore is the only wizard Voldemort fears. As previously mentioned, Dumbledore is as powerful as Voldemort, but this reason isn't the only reason why he fears him (I will not be going into that because I'm focusing on Snape). Where Voldemort has his Death Eaters, Dumbledore has his Order of Phoenix. The only difference is, the Order is secret.

By leaving the Death Eaters, Snape became a member of The Order of the Phoenix. He is still spy for Dumbledore; he manages to find out useful information for the Order to use. Of course, this is all secret so he still has to continue his position as Potions Master at Hogwarts.

During the school term, Harry Potter is receiving visions of what Voldemort is up to and feeling. This is all through his 'connection' with Voldemort, which I will also not go into. One night, Harry witnesses a member of the Order being attacked by Voldemort during his sleep. Feeling this vision important, he immediately meets with Dumbledore (Dumbledore had told Harry about the Order, thinking that the acknowledgement of them was important for Harry).

To prove the vision wasn't just a dream, Harry's story is checked out. It turns out to be true. Upon discussion about Harry being able to see what Voldemort is up to, it is believed that Voldemort can take this in advantage. To prevent him from taking advantage of Harry's visions, Snape is forced to give him lessons on Occlumency.

Occlumency is a method to occlude the mind, to prevent others reading the mind. In these secret lessons, Snape tries to tap into Harry's mind where Harry tries to stop him. Through these lessons, Harry doesn't progess. After many more trials, however, he actually manages to throw back the spell. Instead of all Harry's memories feeding into Snape, Snape's memories feed into Harry.

Harry sees some of Snape's oldest memories. Snape, as a young boy, crying in a corner as his parents argue... Snape, as a teenager, sitting alone in a dark bedroom... Snape, at school, being laughed at while trying to mount a bucking broomstick. From these memories, readers learn of how depressing his childhood was, and have some clue onto why Snape is so dark, mysterious and lonely.

Before each Occlumency lesson, Snape took out memories from his own mind and placed them into his Pensieve (a shallow stone basin able to hold thoughts and memories). One lesson, Snape had unexpectedly been called away, leaving Harry alone in his office with the Pensieve. Being curious, Harry touches the Pensieve, taking him back into Snape's Worst Memory.

In Snape's Worst Memory, we learn exactly why he loaths The Marauders (James Potter, Sirius Black, Remus Lupin, Peter Pettigrew). When Black got bored, James tried to show off. This made Pettigrew laugh and Lupin just ignore it (he was the sensible one of the four). One of the things James used to do to entertain Black was pick on Snape. Snape, of course, fought back, but that still never changed the fact that Snape was severely bullied by The Marauders.

While in Snape's memories, Harry watches teenage Snape being bullied by his father. Near the end of it, the adult Snape catches Harry in his Penseive. Built up with rage and humility, Snape cancels his lessons on Occlumency.

Doing so, Harry isn't able to block out his thoughts from Voldemort. Because of this, Voldemort is able to take advantage and makes Harry see his godfather (Sirius Black) being tortured. Believing the vision to be true yet again, he tries to rescue Black. By going to save Black when he wasn't really being tortured, he lets himself confront the reunited Death Eaters.

Though many questions are answered in book five, several questions are not. Is Snape REALLY working for the Order? Is it only because of Snape's pride that he stops teaching Harry Occlumency? How did Snape win Dumbledore's trust? Should Snape really be trusted? Why did he join the Death Eaters in the first place? If he still gets along with a few Death Eaters (Lucius Malfoy), what is his relationship with the entire clan?

Only the next books can give us the answers.

If I have confused you anywhere in my explanation, mail me or buy the books. Simple. ^-^