It appears that the accidental sale of 14 copies of the latest Harry Potter book at a Coquitlam store last week may have been a marketing blessing in disguise.

Raincoast Books, the Canadian publisher of Harry Potter and the Half-Blood Prince , had gone to court to obtain an injunction to keep the plot secret and get the books back from the "accidental customers."

Coquitlam store where books were sold
Coquitlam store where books were sold

Raincoast also offered a reward to get the books back – a signed bookplate from J.K. Rowling plus other assorted gifts.

The inadvertent sale of the book was news at media outlets around the world, giving the book a massive shot of free publicity.

Company spokesperson Jamie Broadhurst says while it was touch and go for a while, Harry Potter fans have nothing to worry about.

Jamie Broadhurst
Jamie Broadhurst

"At the moment, the secret still remains," he says.

He won't say how many of the 14 books have been returned, but says the people who have returned it are "honourable and obviously have the Harry Potter ethic."

"No one wants to disappoint fans. That's what it all boils down to," says Broadhurst.

But a Simon Fraser University marketing professor says it's not just about the fans. Lindsay Meredith says even Harry Potter couldn't have conjured up a better promotional campaign.

"Talk about falling in a ditch and coming out smelling like a rose. Basically what we have here is some of the best darn coverage to launch a book I think I've ever seen," he says.

"We have national and international coverage for Harry Potter. You couldn't buy advertising that good if you tried."

The latest Harry Potter book officially goes on sale at 12:01 a.m. this Saturday. So far more than 200 million Harry Potter books have been sold.