The only boy who fits the description is Harry Potter: his parents have defied Voldemort three times, he was born at the end of July, Voldemort marked him with a lightning bolt scar and the power Voldemort does not know about is the love of his mother in dying for him.

Dumbledore thinks that the meaning of the prophecy is that, ultimately, Harry must kill Voldemort or Voldemort must kill Harry although there is much speculation as to the meaning of the lines of the prophecy referring to this.

Theories

In the books, a lot of attention in drawn to the fact that Neville is the other boy who could fit the description in the propechy.

Perhaps he is really the one the prophecy is referring to and his poor memory is in some way a mark left by Voldemort. Perhaps Voldemort performed one of the unforgivable curses - Cruciatus or Imperius - on an infant Neville and this caused his poor memory - the mark.

Snape was the one who heard part of the prophecy and passed this information on to his master Voldemort. However, what if, even at this stage, Snape was already a spy working against Voldemort? If he actually heard the prophecy in its entirety - rather than only a part of it, as implied - he would have known that both Harry and Neville fitted the description. Perhaps, somehow, he knew without a doubt that the prophecy referred to Neville and not to Harry. In this case, Snape's continual focus on Harry should prove to contribute greatly to Voldemort's eventual destruction for it pulls all attention away from Neville and provides him with a chance to destroy Voldemort completely. Thanks to Morgan

It is implied by Professor McGonagall in "Order of the Phoenix" that Neville's often poor academic performance is due to a lack of confidence:

There's nothing wrong with your work except lack of confidence."
-Professor McGonagall (Bk 5, pg 232)

The "other" referred to in the prophecy is neither Harry nor Voldemort, but a different person altogether.

Unless this person is killed, neither Harry nor Voldemorte can die. Possibilities:

• The half-blood prince.
• Dumbledore - Voldemort may have somehow discovered the contents of the prophecy, possibly through occlumency or possibly in the brief time which he possesed Harry in the Ministry, and come to this conclusion. For this reason he was so much more keen to kill Dumbledore book 6 than in the previous two.
• Neville

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