Finally got started on this bad boy (7/18), pretty excited

This certainly was one of the darker installment of the Harry Potter series, the young wizard has not grown as much as he was thrown into responsibilities he may not be ready for, we lose a wise voice of reason but alas the path to destroy Voldemort is laid before Harry

As always, Mary GrandPré's illustrations add another layer to Harry's world of wizards

Rowling finally gets a grip on page count with a more reasonable number for Book 6 (source: Amazon)
1: 309 pages
2: 352
3: 448
4: 734
5: 870
6: 652

If you want to spoil yourself further, it is said that page 604 reveals a major plot of the novel

Chapter summary (spoilers)
I have a hard time remembering what happened in the last book so I thought I'd keep some notes about Book 6

Chapter 01 - The Other Minister
Fudge recounds recent events to the Prime Minister, and announces his successor

Chapter 02 - A Spinners End
Snape explains his allegiance to Voldermort

Chapter 03 - Will & Won't
Dumbledore comes to collect Harry and give him his inheritance from Sirius Black

Chapter 04 - Horace Slughorn
Dumbledore recruits a new Hogwarts professor, a dubious character that has strong ties to the Slytherin but who's also taught Harry's mother. Dumbledore tells him he will give him private lessons and has a few words of advice

Chapter 05 - An Excess of Phlegm
Harry arrives at the Weasley house, reunites with his friends and shares the secret of the prophecy with Ron and Hermione. They also complain about Fleur marrying into the Weasley family, receive their OWLs

Chapter 06 - Draco's Detour
Harry and co. head to Diagon Alley for some shopping and the kids end up following Draco in Knocturn Alley where he has a dubious meeting at a store, they don't really know what's going on but Harry is persuaded that something is up

Chapter 07 - The Slug Club
Slughorn invites a few selected students for a chat on the Hogswarts Express, Harry spies on Malfoy but gets discovered and major punk'd

Chapter 08 - Snape Victorious
Harry is bummed to find out that Snape is the new Defense against the Dark Arts teacher (Slughorn is the new Potions teacher)

Chapter 09 - The Half Blood Prince
apparently who the heck is The Half Blood Prince is what this book is about

Chapter 10 - The House Of Gaunt
Harry's first lesson with Dumbledore, actually just trip down the memory lane of the pensieve

Chapter 11 - Hermoine's Helping Hand
Tryouts for the Gryffindor Quidditch team

Chapter 12 - Silver & Opals
A student is jinxed by a necklace on a trip to Hogsmeade

Chapter 13 - The Secret Riddle
Dumbledore shares his first encounter with Tom Riddle (Voldemort) w/ Harry

Chapter 14 - Felix Felicis
Harry makes Ron believe he gave him some of the potion to get lucky so he can have a good day at the first Quidditch game

Chapter 15 - The Unbreakable Vow
Harry follows Snape and Malfoy as they argue about a secret assignment of Draco's, this raises Harry's suspicion of Snape but no one wants to hear it, we find out Snape made an "Unbreakable Vow" with Draco, he could die if he broke it (but we don't find out the detail of the vow)

Chapter 16 - Very Frosty Christmas
Harry refuses to support the Minister of Magic and his current administration

Chapter 17 - Sluggish Memory
Dumbledore gives Harry a mission to uncover a memory that Slughorn has tampered with involving Voldemort

Chapter 18 - Birthday Surprise
Ron is the victim of jinx that has snuck into Hogwarts in a bottle of wine

Chapter 19 - Elf Tales
Harry finds a way to keep tabs on Malfoy by assigning his own house elf Kreacher as well as Dobby to tail Draco

Chapter 20 - Lord Voldemort's Request
Dumbledore shares the memory where he refuses Voldermort's request to teach at Hogwarts

Chapter 21 - The Unknowable Room
Harry finds out that Draco has been hiding out in the Requirement Room

Chapter 22 - After The Burial
Harry uses the Felix elixir to get SLughorn's hidden memory

Chapter 23 - Horcruxes
Dumbledore and Harry explore Slughorn's unaltered memory and find out Voldermort had interest in Horcruxes (splitting his soul in artifacts to excape death)

Chapter 24 - Sectumsempra
Harry gets in trouble for using a hex from the Half-Blood Prince on Draco

Chapter 25 - The Seer Overheard
Harry finds out Draco is almost done as Dumbledore announces he has found one of Voldermort's Horcruxes

Chapter 26 - The Cave
Dumbledore and Harry set off to retrieve one of Voldemort's Horcrux

Chapter 27 - The lightning struck tower
Dumbledore falls

Chapter 28 - Flight of the Prince
The Half-Blood Prince identity revealed, Harry finds out the locket Dumbledore and he found is a fake Horcrux, with a message from a certain R.A.B. inside

Chapter 29 - The Phoenix Lament
Aftermath, recounts of the fight and love triumps while Fawkes the Phoenix chants a sad song

Chapter 30 - The White Tomb
Funeral, conclusion and new resolution for Harry and his friends