BOOK 5 RUMORS
In the fifth book, the Order of the Phoenix, the shadow of Cedric Diggory's living self (NOT a ghost) plays a fairly sizable part in helping Harry over two specific challenges he faces (I don't know what the challenges are however).
This could be the book where a female DADA (Defense Against the Dark Arts) teacher is introduced! Could it be someone we've already met?
We learn more about the background of Lily Potter.
Hermione will be made a Prefect!
I think that the order of the phoenix is a group of very powerful wizard which are there to fight voldemort and his death eaters. dumble dore told Siruis to gather the 'old gang' which I think is the order of the phoenix and consists of the people dumbledore said to gather (Mundunggus fletcher, Siruis, Lupin , Mrs Figg ) and I think that Dumbledore, Lily, James, Mcgongall and other teachers.
Some People are Saying Harry will have a pet dog maybe Sirius to guard him but some are protesting against this as the Hogwarts Letter said you can get A cat, toad or a owl !
About the order of the Phoenix, I think I know why it will be called that. At the end of book four, Dumbledore says, "Time to round up the old crew... Sirius, Lupin, Arabella, (etc.)" These people were the ones who stood up to Voldemort while he was in power. So, they were called the Order of the Phoenix.
In mythology the Pheonix is the most powerful creature because it's immortal, so the order of the Pheonix may be the order of power through the wizard world. A line in which the most powerful wizards are part of.