Still not convinced about e-books? Well it’s time you jumped on the digital bandwagon already – just like everyone’s favourite boy wizard…

Bloomsbury Publishing, responsible for the Harry Potter tales (perhaps you’ve heard of them?), saw their e-book sales grow 1900% in 2010 to £1.5 million. In Q1 2011 alone the company’s digital sales totalled £1.1 million.

The publisher’s so convinced about e-books, they’re setting up a new digital global publisher called Bloomsbury Reader. With offices in both London and New York, they will publish books that are currently unavailable in print where English-language rights have reverted to the author or the author’s estate.

Bloomsbury founder and chief executive, Nigel Newton, recently told the BBC: “Demand for digital delivery, including e-books, is increasing significantly.”

“It will change the publishing business model, creating one worldwide market. The publishing world is handling its own revolution.”

The grand poobah of e-books, Amazon, reported mid-2010 that its digital book sales had surpassed those of hardback books. Fast-forward six months later, and paperback books had also fallen to the mighty e-book.

But wait, there’s more. As recently as last month Amazon’s hardback and paperback sales combined took a tumble.

Amazon founder and CEO, Jeff Bezos, said the growth of digital book sales and Kindle e-readers in the four years since launching had surprised even the company itself.

“We’re grateful to our customers for continuing to make Kindle the bestselling e-reader in the world and the Kindle Store the most popular e-bookstore in the world,” Bezos said.

So far in 2011, Amazon’s US book business has enjoyed its fastest year-on-year growth in over a decade. This includes all book formats, but excludes the many out-of-copyright, pre-1923 freebie reads.

In a recent press release the company revealed the US. Kindle Store boasts more than 950,000 books, including New Releases and all but two of the 100+ New York Times Best Sellers.

But it’s not all about the Kindle, you know. Amazon’s e-books are also available on iPad, iPod touch, iPhone, Mac, PC, BlackBerry, Windows Phone, Android-based devices, and soon HP TouchPads and BlackBerry PlayBooks.

Amazon and Bloomsbury aren’t the only ones pocketing the ker-ching thanks to digital books. Earlier this year the Association of American Publishers (AAP) reported that e-book sales in February reached $90.3 million – in the process becoming the largest single book format. That’s a cool 202.3% growth year-on-year.

“Additionally, trade publishing houses cite ebooks as generating fresh consumer interest in – and new revenue streams for – ‘backlist’ titles, books that have been in print for at least a year,” the AAP said.

“Many publishers report that e-book readers who enjoy a newly-released book will frequently buy an author’s full backlist.”

So do all these impressive numbers equal the death of the paperback? Not so much (sorry trees). Those in the know have made all sorts of wildly differing predictions, the most bullish of which is that e-books will make up 50% of US book sales by 2014-15, and then plateau. The UK, meanwhile, is several years behind the stateside market, but has also seen significant growth since the Kindle was unleashed on the market in late-2010.