Author J.K. Rowling was a single parent, struggling to make ends meet, when her story of a boy wizard first hit bookshelves. In the U.K., it was titled "Harry Potter and the Philosopher's Stone," here, the "Sorcerer's Stone." The book and its sequels eventually took off like a rocket, capturing the imagination of generations of fans and, as the release of the seventh and final book approaches at midnight Friday, it has made Rowling one of the richest people in the world, sparked an unfathomable following of devotees and kept many fans up at nights, reading as soon as each book landed in his or her hands.

We expect that will be the case with No. 7, "Harry Potter and the Deathly Hallows," too. Just in case you've missed the hugely successful books, with their familiar illustrations by Mary GrandPre; movie series; or audiotapes narrated by the award-winning Jim Dale, here's a refresher course on what happens in books 1 through 6.

No. 1. "Harry Potter and the Sorcerer's Stone"

It began with magical folk delivering a baby -- "the boy who didn't die" -- to the doorstep of those awful Muggles (non-wizards), the Dursley family. That boy, Harry, sports a lightning-shaped scar and lives under the dreadful thumb of his aunt, uncle and cousin until his 11th birthday, when he is fetched by the gentle giant Hagrid to the Hogwarts School of Witchcraft and Wizardry to begin his proper education.

Here Harry (and we) meet the fabulous cast of characters who become his friends and enemies. In the first camp, Ron Weasley and Hermione Granger quickly become Harry's best chums, along with wise headmaster Albus Dumbledore and stalwart Professor McGonagall. Another professor, Snape, immediately sets about making Harry's life miserable, along with some nasty schoolmates, led by Draco Malfoy. Here we learn of the sport of Quidditch, spells, potions, magical creatures and, most of all, of the enemy to everyone's peace and safety, the dark and murderous Lord Voldemort, who killed Harry's parents and came to be known as He Who Must Not Be Named.

But as Harry learns, among many other lessons, saying that name is the least of his worries -- he has his first encounter with the dark lord since the day his parents were killed. Harry survives again, and now he knows what evil is afoot.

Book 1 numbers: Published in 1998, 50,000 copies in initial print, 309 pages, original hardcover price: $16.95.

No. 2. "Harry Potter and the Chamber of Secrets"

Part of the purpose of "Chamber" is to reveal Voldemort's dark past -- along with how Hagrid came to be at Hogwarts in the position of groundskeeper and so devoted to Dumbledore. Ron's sister, Ginny, plays a role as a pawn for Voldemort's actions, but her role in Harry's life is to become more important later.

The book opens near the end of Harry's miserable summer, when he is visited by a strange, impish creature named Dobby, who begs him to stay away from Hogwarts if he wants to live. Harry learns that Dobby is right: Someone is trying to harm him, even as other Hogwarts students are turned to stone.

As Hogwarts' staff struggles to keep its students protected from the evil flourishing in their midst, Harry and his friends Ron and Hermione decide to take action.

Book 2 numbers: Published in June 1999, 250,000 copies in initial print, 341 pages, original hardcover price: $17.95.

No. 3. "Harry Potter and the Prisoner of Azkaban"

Returning to Hogwarts for his third year, Harry, now 13, finds that the school is being guarded by the deadly Dementors. There's been a break-out from the horrific wizard prison called Azkaban, and the Dementors have been sent -- against the protests of Headmaster Dumbledore -- to keep the Hogwarts school safe from Sirius Black, the escaped prisoner.

Before the book ends, Harry learns the truth about Sirius. He also learns that he must guard against the power of the Dementors, who can suck out people's souls. And Harry once again must find a way to conquer Voldemort, who has used a servant to try to gain power over the boy wizard.

Book 3 numbers: Published in September 1999, 500,000 copies in initial print, 435 pages, original hardcover price: $19.95.

No. 4. "Harry Potter and the Goblet of Fire"

Harry is troubled by pain in his scar all summer, and when he returns for his fourth year at Hogwarts (after attending the Quidditch World Cup with the Weasley family), the pain gets worse. Harry understands that his scar somehow links him to Voldemort, and he anxiously wonders what the pain might mean.

Still, Harry is able to put aside his worries as his interest in girls increases. He also has another concern: He's mysteriously become the second of two Hogwarts representatives who must compete with students from two other European wizarding schools in the Triwizard Tournament.

In the tournament, the students must use their wits to complete three seemingly impossible tasks. But things go haywire in the end, a student dies, and Harry again finds himself face-to-face -- and wand-to-wand -- with the increasingly powerful Lord Voldemort.

Book 4 numbers: Published in 2000, 3.8 million copies in initial print, 734 pages, original hardcover price: $25.95.

No. 5. "Harry Potter and the Order of the Phoenix"

Now 15, Harry finds himself in a magical world that is bitterly divided over whether Voldemort really has returned to strength. Harry has seen this for himself, but others in the wizard world, including top government officials, refuse to accept this fact.

Harry has other problems: His efforts to date Cho Chang are only intermittently successful. More disheartening, Hogwarts has been taken over by a Ministry of Magic official named Dolores Umbridge, who sadistically delights in physically and verbally abusing students.

Eventually, things come to a head and there is a deadly battle -- in the Ministry of Magic building -- between Harry and his friends, joined by members of the Order of the Phoenix, and Voldemort. Harry's godfather, Sirius Black, is killed in the battle.

Later, when they are alone, Dumbledore apologizes to Harry for neglecting him during the school year and reveals what Voldemort was seeking in the Ministry: a prophecy that says "either must die at the hand of the other for neither can live while the other survives."

Book 5 numbers: Published in 2003, 8.5 million copies in initial print, 869 pages, original hardcover price: $29.99.

No. 6. "Harry Potter and the Half-Blood Prince"

If you are reading Book 6 now, SPOILER ALERT!

Snape, the Potions professor in previous books, finally gets his wish and becomes the Defense Against Dark Arts teacher at Hogwarts. Harry finds a used potions book in which someone who calls himself "the Half-Blood Prince" gives helpful potion tips and spells. The "prince," Hermione discovers much later, turns out to be Snape.

Meanwhile, Dumbledore gives Harry private lessons -- about Voldemort. The now 17-year-old Harry also learns about Horcruxes: divisions of the soul created when a person murders someone. Voldemort's must be destroyed to kill him.

Draco Malfoy is sent to kill Dumbledore and bring Death Eaters into Hogwarts. It's Snape, however, who completes the job. In a monumental battle, students, teachers and other good guys force the Death Eaters to flee.

Dumbledore is mourned. It is unclear if Hogwarts will reopen. Harry and Ginny admit feelings for each other, but he is cautious because Voldemort will use people he loves against him. Whether Ron and Hermione will be together is unclear. Harry vows not to return to school but to track down the remaining Horcruxes and defeat Voldemort.

Book 6 numbers: Published in 2005, 10.8 million copies in initial print, 734 pages, original hardcover price: $29.99.

No. 7. "Harry Potter and the Deathly Hallows"

Happy reading!

Book 7 numbers: Released Saturday, July 21, 2007. 12 million copies in initial print, 784 pages, original hardcover price: $34.99.