Though the rags to riches story of its author was well on its way already, many readers in North America got their first dose of "The Boy Who Lived" 20 years ago today.

The first installment in J.K. Rowling鈥檚 groundbreaking series -- Harry Potter and the Philosopher鈥檚 Stone (or Sorcerer鈥檚 Stone in the U.S.) -- was published on Sept. 1 in 1998, a year after its original publication in England.

The series鈥 influence is undeniable. It turned a single mother living on welfare into a philanthropist and literary icon . It sold more than 500 million copies, becoming the highest-selling book series of all time. It spawned a blockbuster film franchise, grossing nearly US$8 billion worldwide (without adjusting for inflation).

Most strikingly, the books are often credited for causing a 鈥渢itanic change鈥 in reading culture. That鈥檚 not just according to New York Times literary critic Charles Finch, who spoke with 麻豆影视 Channel on Saturday, but even research indicates the millennial generation reads .

鈥淚n virtually every way for children and adults the most important event of our lifetimes is Harry Potter,鈥 said Finch. 鈥淭here鈥檚 a whole range of people from the age of about 10 to 40 who fell in love with reading because of those 500 million copies.鈥

Finch credits the series for launching a kind of 鈥渃ross pollination鈥 of reading audiences bringing together not only children and adult readers but bringing adult themes into children鈥檚 fiction.

鈥淪ince the success of the initial book 鈥 there has been much more openness to crossover between serious subjects in young adult literature and adult readers,鈥 he said, noting recent successful authors like John Green (The Fault in Our Stars) and Angie Thomas (The Hate U Give).

And while every Harry Potter fan will have their own personal favourites, Finch said the character with perhaps the most striking influence on a generation of readers isn鈥檛 the title character himself, but one of his sidekicks: Hermione Granger, the frizzy-haired academic played by Emma Watson in the film series, who Finch described as 鈥渁 young girl who wasn鈥檛 afraid to be the smartest in class, wasn鈥檛 afraid to speak her mind.鈥

鈥淚t鈥檚 a huge credit to J.K. Rowling that she created this character who鈥檚 given young girls and now young women everywhere a lot of strength,鈥 he said.