The Half Blood Prince's Potion Book...

so i guess, it's mine tom.

NEVER! Voldemort would have never called himself half blood!

I thought his specialty was the one that lifts people by the heels.

Angry, resentful, distraught, but you'll note that he never used it. Just fantasized about it. There is a difference.

It was in the standard, 6th year potion book. And left in a pile with a bunch of others. Had Snape known it was there, he would have removed it. He would not add to it over the years and then casually leave it around like that.

Again, that was the heel thing.

EXACTLY - Voldemort couldn't bear being a half-blood! Didn't work out who's book it was for a while. Snape probably forgot it was there - he'd been potions master for a long while!

It was pretty obvious that it was snapes book. When he was young his fav lesson was potions, wud he pu in all that extra work on any other subject, and thier had to be a reason why he was so accomplished at it as wel. Plus the dates added up to whenhe was at hogwarts. It cud have been Voldemort, but he was to interested finding out about horcurxes, and world domination to bother making new spells, or finding the best way to improve a potion.

Snape's favourite lesson may have been potions, but didn't he apply for the job of DADA teacher?

YES!

I don't know if I made this up or where I read or heard it but,

Snape was refused the post as DADA teacher as it was cursed by Tom Riddle!

Every person who took that position was due to meet a deadly demise or (in Remus' case) near fatal injury.

This was because Tom wanted the position to himself so that he could infiltrate the minds of the young and vulnerable and begin to build his army.

Good Grief !!! wait ..that's Book 6 isn't it ...Dumbledore telling Harry...right? Blending to much Canon with fiction lol!

The position was cursed AFTER tom asked for the job and was refused, so in a mater of speaking he could have been the one to curse the job. But snape was dened the DADA job, as dumbleodre believed that if he taught it he would have a relapse and devote himself to voldemort again, so he kept him away from temptation.