Voldemort and Immortality

Quote	Source
"I miscalculated, my friends, I admit it. My curse was deflected by the woman's foolish sacrifice, and it rebounded upon myself. ... What I was, even I do not know ... I who, have gone further than anybody along the path that leads to immortality. You know my goal - to conquer death. And now, I was tested, and it appeared that one or more of my experiments had worked."	Book 4, Page 653 Goblet of Fire, Chapter 33, "The Death Eaters"
"I did not manage to steal the Sorcerer's Stone. I was not to be assured immortal life. I was athwwarted ... thwarted, once again, by Harry Potter..."	Book 4, Page 654 Goblet of Fire, Chapter 33, "The Death Eaters"
"There was no hope of stealing the Sorcerer's Stone anymore, for I knew that Dumbledore would have seen to it that it was destroyed. But I was willing to embrace mortal life again, before chasing immortality. I set my sights lower... I would settle for my old body back again, and my old strenth."	Book 4, Page 656 Goblet of Fire, Chapter 33, "The Death Eaters"
"My mother can't have been magic, or she wouldn't have died," said Riddle, more to himself than Dumbledore.	Book 6, Page 275 Half-Blood Prince, Chapter 13, "The Secret Riddle"
"Well, Harry," said Dumbledore, ... "At the same age as you are now, give or take a few months, Tom Riddle was doing all he could to find out how to make himself immortal."	Book 6, Page 499 Half-Blood Prince, Chapter 23, "Horcruxes"