The BBC has reported that the value of digital fiction sales in the first half of 2012 was up 188% on the same period in 2011.
Physical book sales saw a drop in value, dipping 0.4% year on year.
Industry experts said that while the figures were healthy, other areas of the industry, such as bookshops, continued to struggle financially.
"Certainly the strong e-book growth has taken the tarnish off the otherwise tricky market," said Philip Jones, editor of The Bookseller.
"It is good news that the market is transitioning and making money from that, but it is moving to a trickier situation where there are fewer booksellers."
The figures show impressive increases across the board in a year where e-book popularity, in particular the likes of Fifty Shades of Grey, hit the headlines for racking up massive sales.
Sales of digital children's books were up 171%, while non-fiction titles increased by 128%.
'Exciting authors and titles'
The total value of sales of all books, digital and non-digital, were up by 6.1% for the January-June period.
This generated revenue of £1.1Bn for the first half of the year, the Publishers Association (PA) said.
"The huge increase in digital sales shows how rapidly readers and publishers are embracing e-book reading," said Richard Mollet, the trade body's chief executive.
"Whether books are enjoyed physically or electronically, publishers will continue to invest in exciting authors and titles.
"They can do this because of the stability provided by the UK's robust and flexible copyright framework.
"This is why the PA is at the forefront of calls to government to ensure that copyright is not eroded and that creators' rights are protected and supported online."
Jones, also said that independent bookshops were struggling to keep up with their larger rivals such as Amazon.
Some other shops, such as Waterstones, are aiming to increase sales by entering into tie-up deals with popular e-book manufacturers.
The industry is unsure, Mr Jones said, over where exactly consumer interest will head next.
"What we don't know yet is what will happen when more book readers get tablet devices," he said.
"This will be the first Christmas where you get more cheap tablet devices from the likes of Barnes and Noble, Amazon and Kobo.
"There's a good deal of uncertainty about what will happen on Boxing Day 2012 when a few million people open up their tablet and think 'What am I going to buy on it?'."