Answers will be provided when J.K. Rowling reads from the next Harry Potter adventure at the Royal Albert Hall on June 26, and does a live interview about the book that will be broadcast simultaneously on the Internet.
At the event, hosted by actor Stephen Fry, Rowling will read from "Harry Potter and the Order of the Phoenix" - which is to be published June 21 - before taking questions about junior wizard H. Potter from members of the audience and through the Internet.
British Telecom is sponsoring the webcast and Microsoft is hosting the online event at www.msn.co.uk/harrypotter. Rowling's British publishers, Bloomsbury, have commissioned the companies Initial and Victoria Real, which made the "Big Brother" reality series for TV, to film the event.
"There isn't a venue anywhere in the world that could host the millions of Harry fans over the world desperate to experience the magic of this event," said Tracy Blacher, MSN marketing manager.
"This is what the Web should be about - taking fans to the heart of the action whether they're in Houston, Harrogate or Hong Kong."
More than 900 schools applied for the 4,000 tickets to attend the event.
The Web cast, which is free, begins at noon EDT. Microsoft said it has the potential to reach children in 34 countries in 18 different languages.
Before the event, children are invited to submit their questions about Harry to the Web site. Fry will put the best questions to J.K. Rowling live on the night. A number of questions will also be taken live from the Internet during the webcast and fed through to the author during the event.
Harry fans will also have the chance to win bookplates signed by the author.
The webcast will be archived for seven days after the event so fans can watch it again.
Peter Cowley, Director of Interactive Media at Endemol - parent company of Initial and Victoria Real - said the event "is an example of the Web doing more than television could ever do - beaming out a hugely anticipated event directly to a worldwide audience, free of charge."
"Harry Potter and the Order of the Phoenix" is over 255,000 words compared with over 191,000 words in Rowling's fourth Potter book, "Harry Potter and the Goblet of Fire." Released in July 2000, that sold more copies on the first weekend after publication than any other book, according to Bloomsbury Publishers.
Rowling's four published titles have sold an estimated 192 million copies worldwide in hard and soft cover, and the books have been published in at least 55 languages and distributed in more than 200 countries.
In addition to the United States - where it is published by Scholastic - and Britain, the new book also will be published on June 21 in Canada, Australia and several other countries.
By Sue Leeman