David Heyman: Tanya Seghatchian, my very bright development executive, read an article in a trade publication about a book that hadn’t yet been published. She called the agent. The book came in and sat firmly on the low priority shelf for a couple of weeks before Nisha, my secretary, who only read material from that bottom shelf, took it home. At our Monday morning I asked, "Anybody read anything good?” And Nisha replied, "Yeah, I read Harry Potter and the Philosopher’s Stone.” I said, "Hmm, not sure about that title. What’s it about?” "It’s about a young boy who goes to wizard school,” she replied. My interest was piqued.

I took it home that night and I fell in love. I couldn’t put it down and there began my Potter odyssey. I sent it to a friend of mine at Warner Bros, Lionel Wigram, whom I had known since I was 14. He responded, but I’m not sure many others at the studio really got it at the time. It hadn’t yet become a phenomenon.

What I did know was that I connected with it. It made me laugh. It moved me. I related to Harry and the characters at Hogwarts. We all, in our own way, feel like outsiders. And no matter who we are, no matter how successful, no matter how happily married we are or what good friends we have, there are times where we feel alone. At least I do. And I felt that story was something that people could connect with. It was about something: being true to yourself. It was about loyalty and friendship and fighting prejudice and so much more.

Heyman: Kloves delivered the script towards the end of 1999 and it was wonderful. Warners green-lit it immediately. We met a few directors and decided on Chris Columbus. He was such a passionate fan and wanted above all to be respectful of Jo and true to what she had written. Chris was beyond generous to me. He embraced me as a partner in the process and I learnt so much from him. The first person we hired was Stuart Craig, the great production designer.

Then we began casting, scouring the U.K. to find our three young leads. By June, we felt like we had good options for Ron and Hermione but we didn’t have our Harry. We even, out of desperation, expanded the search to the U.S., Australia and New Zealand. We looked everywhere. And here we were, less than 10 weeks before filming. It was a scary time indeed … we were making a film called Harry Potter and the Philosopher’s Stone and we didn’t have our Harry Potter.

One evening, Kloves and I went to the theater and seated in the audience, I noticed this boy with big round blue eyes. He seemed an old soul in a young body. And then this voice called, "David, great to see you.” Sitting next to the boy was his father, an agent I knew called Alan Radcliffe. The play started but I paid little attention to what was going on up on stage. I kept on turning around and looking at this boy. When the play finished, I went to find Alan and his son, but they’d gone.

So the following morning I called ICM and asked if Alan would allow Daniel to visit the studio to meet Chris. Alan said, "Why don’t you meet him first, and then we can decide.” So Dan, his mum and I went out for a cup of tea and we spent two hours chatting. Dan had this incredible energy. He was so curious and intelligent—a curiosity and intelligence that have helped make him the actor he is today.

Afterwards Alan agreed that Dan should meet with Chris, who really liked him—actually Chris had spotted him in a production of Great Expectations but been told that he didn’t want to audition for Potter—and brought him in for the final auditions. Chris looked at three kids for each part, in different combinations. When we screened the footage, it was clear to all Emma and Rupert were our Hermione and Ron. But there were some who weren’t so sure about Harry and so I suggested we sleep on it.

The following morning we watched the screen test again and Chris announced, "It’s Dan Radcliffe.” Phew! We couldn’t have done better! A couple of days later we had to do a press conference and the journalists were asking all sorts of inappropriate questions. I’ll never forget, one asked Rupert, "So how much are you making for this?” and this 12 year old boy quips, "You know, I don’t know how much in Muggle money, but I do know in Knuts and Galleons, if you want.”

Then we cast the other roles. Every adult we approached wanted to do it because their children or grandchildren wouldn’t have it otherwise. Richard Harris agreed because his granddaughter, Ella, said she wouldn’t talk to him if he said no.

Heyman: The story takes place 70-plus years before Potter. It’s inspired by a book that Jo wrote for comic relief. It’s "authored” by a man called Newt Scamander, who’s a magizoologist, and it’s a story of his adventures in New York in the 1920s. It’s funny and thrilling and fresh and original, and features adults, not children. I think it will be enjoyed by Potter and "non-Potter” fans alike.

[laughs] I hope so. It’s rich and resonant, and fun and moving. It’s a really delightful mix. And its great to be back in Jo’s wizarding world and to be working with David Yates again.