It's been said for a long time that the Harry Potter books by J.K. Rowling have grown in maturity as their readers grew up, and the newest book is no different. The conclusion of the septology shows a side of the characters that is more realistic of 17-year-olds than most parents of younger readers would like.
This book is no Sorcerer's Stone,"" and if rated in the same system as television shows it would garner an 'M' without any questions asked (PG-13 as a movie though, there's no nudity). There is (in comparison to what's normally expected out of a ""children's book"") hard profanity, gratuitous violence and heavy sexual innuendo, and it all makes for the perfect conclusion to stories that are so pervasive in American culture they're actually required reading for entering freshman at many universities and colleges.
""Harry Potter and the Deathly Hallows"" departs from the previous books in other ways - there's no quidditch, and the only scenes at Hogwarts are in the last chapters. While this probably disappointed a few fans, it also has the effect of pushing the book away from the others, making it a more unique part of the series.
The narrative style, however, is on the same path as the previous books. It begins in mid-summer and finishes the same time the next year (minus the epilogue). It's justifiable and necessary that Rowling would keep this style of time, but it diverges again from the previous books in that it seems she had some trouble filling the pages. Too frequently are the characters simply wandering from place to place, with no seeming purpose behind their motives, making Rowling seem a little anxious to get the characters to the final chapters in June.
This is theoretically to be the last book in the series, and fan websites were shoving out theories on how she would conclude it en-masse. Rowling never indicated throughout the series how it would conclude, and the final epilogue that she chose to write worked about as well as any Potter-head could ask for. ""Harry Potter and the Deathly Hallows"" had more plot devices than a season of ""Lost,"" and she somehow managed to close them leaving the reader only disappointed that it's over.
This book series is one thing that defined our generation (I'm personally looking forward to the VH1 flashback in 15 years), and with the final conclusion of this we only have two more lowly movie openings to look forward to.
The books were lucky, the witches and wizards never need technology since they have magic, so they never had the issue of dating themeselves into obscurity. Future generations will no doubt read and love this series as much as any person who read this the first day of its release, hopefully they just wait until they're a little older to get to ""Deathly Hallows.