The year she turned 11, Nicole Mok waited for the letter that would tell her she could go to Hogwarts, the wizarding school attended by Harry Potter, from the phenomenally popular books of the same name by British author J.K. Rowling.

Ms Mok, now 26 and between jobs, is part of the "Harry Potter generation", who first cracked the books' covers as children and are now, like Harry himself would be, adults.

The boy wizard marked his 20th anniversary yesterday, 20 years to the day Bloomsbury published Rowling's first book, Harry Potter And The Philosopher's Stone.

Much has happened since. The seven books have been adapted into eight blockbuster films and spawned theme parks, exhibitions and merchandise the world over.

Spin-offs just last year include a West End play, Harry Potter And The Cursed Child, and a new film series, Fantastic Beasts And Where To Find Them.

Rowling, 51, has gone from being a single mother living on state benefits to a multi-millionaire.

But for many from that first generation who waited for their Hogwarts letters, the magic of the books is still alive.

Ms Mok, who in 2007 queued overnight at Borders bookstore and was the first to get her hands on the seventh book, Harry Potter And The Deathly Hallows, says: "I think we were a very lucky generation. Without these books, the world of literature would be very different for children."

To mark the anniversary, Bloomsbury has released a new edition of Philosopher's Stone in the colours of the four Hogwarts houses Gryffindor, Hufflepuff, Ravenclaw and Slytherin.

Rowling last week launched the online Wizarding World Book Club on her website Pottermore, which encourages fans across the world to discuss the books by setting weekly themes.

The British Library in London will also unveil a new blockbuster exhibition, Harry Potter: A History Of Magic, in October.

It will feature some of the library's centuries-old treasures, such as a massive 16th-century Ripley Scroll, in which alchemist George Ripley explains how to create a Philosopher's Stone, alongside original items from Rowling's own archives, such as a handwritten draft of the Sorting Hat song.

This weekend, an international concert series, in which a live symphony orchestra performs at a film screening of Philosopher's Stone, will make its way to Singapore's Esplanade Concert Hall. The concert series began in June last year in the United States and will make its way to more than 35 countries.

The concert's producer Brady Beaubien says: "More than any other literary or cinematic world in my lifetime, J.K. Rowling's world of Harry Potter has inspired people's imagination and sense of possibility. To return these films and memories to fans and help them make new memories is a true privilege."

Businesses in Singapore are organising their own events around the anniversary. Bookstores such as Books Kinokuniya and Times are offering discounts and promotions on the Potter books, while children's bookshop Books! Ahoy is hosting a Hogwarts House Party next month to coincide with Rowling's and Harry's shared birthday on July 31.

Last Tuesday, a group of Singapore Polytechnic finance students organised a Harry Potter tea party for about 35 guests at Platform 1094, a wizard-themed cafe in Boon Keng.

The cafe, which opened in December at 1094 Serangoon Road, is named after Platform 93/4, a magical platform at London King's Cross railway station from which the Hogwarts Express departs.

At the party, guests ate canapes resembling the Golden Snitch, a winged ball in the wizarding sport of Quidditch and hunted for "Horcruxes", magical items which must be destroyed to defeat the series' villain, Voldemort.

Singapore even has its own version of the wizarding world in Harris Bin Potter And The Stoned Philosopher, a parody by Singaporean writer Suffian Hakim. In it, the hero lives in a cupboard under the sink in a Tampines flat, Hogwarts becomes Hog-Tak-Halal- What (hog not being halal) and wands are satay sticks infused with magic.

A magical childhood for many

The 30-year-old, who writes full-time, began the spoof in 2009. After chapters of it went viral online, it was published in 2015 by crowd-funding platform Publishizer and has since entered a third print run.

"Harry Potter will always be relevant," says Suffian, who has taken rides on the MRT dressed in wizard robes with a lightning bolt-shaped scar on his forehead. "Family, friendship and love - for me, no other book has been able to combine those themes so well and still be so engaging."

The Harry Potter books have sold more than 450 million copies worldwide and been translated into 79 languages. Deathly Hallows holds the record for the fastest-selling book in history, moving 11 million copies in the first 24 hours of release.

Though exact sales figures for Singapore alone are unavailable, booksellers estimate that more than 1.5 million of the first six books were sold in the first eight years. The sixth book, Harry Potter And The Half-Blood Prince, sold about 200,000 copies when it came out. In the last year, more than 100,000 Potter books have been sold, including special editions and box sets.

Nothing could be further from this immense success than the books' first modest arrival in Singapore. Distributor Pansing brought in fewer than 100 copies of the first two books. Even then, selling them was an uphill task.

Book industry veteran Rudolf Phua, who founded Pansing, recalls how he was "more than a little sceptical". Bloomsbury, says the 74-year-old, was a very young company with literary leanings, for which children's books were out of character. What was more, the book titles were a mouthful. Everything seemed wrong.

"I suspect even Bloomsbury itself did not realise what an extraordinary product it had," he says.

By the launch of the third book, Harry Potter And The Prisoner Of Azkaban, attention had snowballed worldwide. Pansing took a gamble on bringing in 150,000 copies of Harry Potter And The Order Of The Phoenix in 2003, spending an unprecedented $250,000 on publicity. The books had to be kept in secure, top-secret locations around the island for two weeks until the launch.

It was an unnerving time for Mr Phua and his team because earlier that year, the Sars (Severe Acute Respiratory Syndrome) outbreak had crippled the retail trade. "Many retailers, including booksellers, were staring bankruptcy in the face, with sales down to a mere fraction," he says.

But on the morning of the launch, the entire book trade heaved a sigh of relief as customers came out in droves to snap up Order Of The Phoenix. "That book sort of broke the fear that had kept customers away from shops."

Harry Potter's local success was also tied to the rise of bookstores such as Borders and Books Kinokuniya's main store, which opened in the same years as the first and third book respectively, says Kinokuniya's store and merchandising director Kenny Chan.

"It opened up a love of reading among younger non- readers and started the Dumbledore Reading Army, so to speak," adds the 64-year-old, riffing on the secret student organisation Harry starts in his fifth year.

Among these young readers was retail executive Chin Xuan, 25, who grew up in a Mandarin-speaking family and was not keen on reading. After watching the first movie when she was 11, however, she started reading the books and was hooked.

What drew her in was the way the books mirrored her experiences as she grew up. The end of the seventh book, she says, was "the end of my childhood", although she appreciates how the Fantastic Beasts film now centres on characters in the working world, which her generation has entered.

She and her friend, marketing officer Jo Chua, 36, have between them more than 450 Harry Potter collectibles, more than a third of which they loaned to the Singapore Philatelic Museum for the Collecting Magic: From Stamps To Wands exhibition, which ran from November to June 18 and saw 83,000 visitors.

Ms Chua, who queued overnight for the last three books and sat through a 25-hour marathon of all eight movies at Golden Village's VivoCity cinema, made many of the collectibles herself, such as a Lego set of wizarding shopping district Diagon Alley.

The official set has three buildings, but Ms Chua expanded this to 10 over three months, specially shipping in tiny spare bricks.

She has also made three costumes for reporter Rita Skeeter, Hogwarts professor Minerva McGonagall and, recently, Magical Congress of the United States of America president Seraphina Picquery.

"It brings me closer to the world," she says. "In a way, it is like escaping into childhood."

Ms Chin agrees. "If bad things happen to me, I read the books and they are my support. Whatever happens, Hogwarts will always be there to welcome us home."

With all the fanfare around the Fantastic Beasts franchise, which Rowling wrote the first screenplay for and has confirmed will stretch to five films, the books seem to be falling behind.

Sales of spin-off books such as the Cursed Child script and the Fantastic Beasts screenplay have not fared as well locally. Kinokuniya's Mr Chan estimates that sales for the former are half those of one of the original books, and the latter even less.

But because of children such as 12-year-old aspiring Ravenclaw Janine Shum, the magic will persist for another generation. Her mother, housewife Shum Fung Sing, 41, read the first book with her when she was eight. They have since made pilgrimages to the Warner Bros studios and theme parks in London, Los Angeles, Osaka and Orlando, so Janine could feel like she had been to Hogwarts.

"I treasure that bit of childhood, the curiosity, imagination and wonder," says Mrs Shum, a former literature curriculum specialist. "Put any avid reader of the books into a Hogwarts robe. Give him a wand. Give her a time-turner. And suddenly, magic."

Magical events

HARRY POTTER FILM CONCERT

Watch Harry Potter And The Philosopher's Stone movie accompanied by a symphony orchestra performing John Williams' iconic score.

Where: Esplanade Concert Hall, 1 Esplanade Drive When: Saturday and Sunday, 7pm Admission: $255, $185, $105 from Sistic (call 6348-5555 or go to www.sistic.com.sg) Info: harrypotterinconcert.com

BOOKS AHOY! HOGWARTS HOUSE PARTY

Compete for the House Cup through transfiguration classes and a fan quiz. Take part in a costume contest at this afternoon party for all ages at children's bookstore Books Ahoy!.

Where: 02-03 Forum The Shopping Mall, 583 Orchard Road When: July 30, 4 to 6pm Admission: $10, inclusive of $5 store credit to be used that day. Go to bit.ly/2rYk90b Info: Call 6222-9980 or e-mail sayhello@woodsinthebooks.sg

BOOKS KINOKUNIYA CELEBRATION

Books Kinokuniya's Jurong store will be holding a Sorting Hat ceremony and a Golden Snitch hunt, along with freebies such as house stickers, fan-art wands and special house crest stamps. The store will also sell exclusive, limited-edition merchandise, such as chibi badges and a chess set, that weekend.

Where: 04-23 Jem, 50 Jurong Gateway Road When: July 30, 10am to 9.30pm; Sorting Hat ceremony is at 3.30pm and Snitch hunt at 4pm Admission: Free Info: kinokuniya.com.sg

HARRY POTTER: A HISTORY OF MAGIC

For those travelling to London later this year, the British Library will be opening a blockbuster exhibition on wizarding books, manuscripts and magical objects, combining some of the library's centuries-old treasures with original items from Bloomsbury and author J.K. Rowling's own archives. The exhibition's structure is inspired by the Hogwarts curriculum, including subjects such as Potions, Herbology, Astronomy and Care Of Magical Creatures.

Where: The British Library, Paccar Gallery, 96 Euston Road, Kings Cross, London, Britain When: Oct 20 to Feb 28 next year Admission: £16 (S$28) for adults, £11 for seniors aged 60 and older, £8 for students and children aged five to 17, free for children four and younger. Buy tickets at bit.ly/2oycgwD Info: www.bl.uk/harry-potter