As the blockbuster 'mummy porn' hit Fifty Shades Of Grey remains the top-selling e-book of all time, Hannah Stephenson discovers more downloadable summer hits, while two reviewers give their opinions on the pros and cons of the e-reader.

By Hannah Stephenson

Less than two years after they were launched, it's estimated that more than 807 million people worldwide own some sort of e-reader - and many will now be downloading a stack of titles to take with them on holiday.

The boom has allowed previously unknown authors to make it big, as has been proved by the phenomenal success of the erotic Fifty Shades Of Grey trilogy by E L James, who used the self-publishing arm of Kindle to become the first person to sell more than one million e-books.

Earlier this year publishers scrambled to sign sports journalist Kerry Wilkinson after the runaway success of his self-published e-book Locked In, the first in the Jessica Daniel detective series. The book sold a staggering 250,000 e-books in six months.

His strategy involved selling the first novel at a bargain 98p (the follow-ups cost more), and marketing it using his own website and social media. Now the backing of publishing giant Macmillan could propel him into the same league as Lee Child and Martina Cole.

The e-reader has come a long way in the last two years, with competition hot among Kindle, Sony, Kobo and others. As well as finding new authors, a number of e-book sellers offer free downloads of classic books which are out of copyright.

It also appears to be changing the genres people are happy to buy. Downloading saucy stories is becoming increasingly popular with women, for example, as the anonymity of the transaction means they are spared the blushes of having to buy a sexy book at the till.

The future of the e-book is undoubtedly rosy (one in 40 adults in the UK received an e-reader for Christmas) but could it ever replace the traditional print book?

Sophie Poderoso, PR manager for Kindle, says: "For some people, it already has, even people who were initially technophobic. It's all about getting you closer to the author's words and enabling people to read more.

"Since Kindle launched, people are reading four times as many books. It means there's a real renaissance in reading and that can only be good."

But not everyone is a devotee of the device, as our reviewers demonstrate.

For and against e-readers

:: Why I Love My Kindle, by Cathy Gordon

As an avid holiday reader my Kindle has proved to be indispensable. It was quite a while before I took the plunge and bought one, because I thought it could never replace the pleasure of holding and reading a real book. But I decided to bite the bullet after lugging several large paperbacks on a two-week break in the sun, only to find that I had run out of things to read days before I was due to fly back home. So, the next time I fled these rainy shores I was armed with my new toy. Before I went I downloaded several weighty tomes I thought I may like to read, planning to broaden my mind. However, once stationed on my sunbed, all I wanted was a good old thriller to go with my ice-cold beer. Kindle to the rescue! After a quick search in the Kindle shop I made my choices, at very little cost, and within a matter of seconds they miraculously appeared - and I was able to lose myself in the murky world of crime. I have found it particularly useful for short breaks abroad via a low-cost airline when I am just travelling with a cabin bag and want to travel as light as possible.

:: Why I Prefer Traditional Books, by Hannah Stephenson

I recognise the weight-saving, space-saving values of taking an e-reader on holiday, but there's nothing like a the feel of a real book to get you in the mood for reading.

I have long resisted the e-reader partly because I spend so long on a screen at work that I don't want to resort to a screen in my free time. I love the feel and even the smell of books, the comfort and cosiness those real pages can create, the fact that you never have to plug anything in to charge and that the batteries never run out.

Trialling the new Kindle Touch, I found the black and white format uninspiring, with choices having to be made in monochrome, yet part of the fun of choosing a new book is surely to see the cover in all its colourful glory. I'd need to go to a bookshop to make my choice before I downloaded it on to my e-reader and that would be a palaver.

When I go to bed I want to look forward to choosing from a pile of books on my bedside table, not a tablet. It's just a turn-off. It doesn't inspire me to read.

While other readers may be piling their mass market disposable Dan Browns and Jilly Coopers onto their tablets for their holidays, I'll be borrowing my choices from friends and family or treating myself to a new paperback, which I can then pass on to others to enjoy.

Something for the sunbed

If you do have an e-reader, here are just a few of the summer e-books which may take your fancy:

:: The Tattooist, by Louise Black (Cutting Edge, Kindle edition 77p): If you liked Fifty Shades, you may want to try this disturbing, erotic tale of how three very different women fall under the spell of Fabrice, a tattooist who will leave his mark on them forever.

:: Broken Harbour, by Tana French (Hodder, Kindle edition £6.99): Page-turning psychological thriller from the Irish novelist. When a father and his two children are found dead and the wife is taken to hospital it initially seems that the father, a casualty of the recession, murdered his two children and tried to murder his wife before killing himself. But soon the top Irish detective Mike 'Scorcher' Kennedy finds pieces of the puzzle just don't fit and the case leads to repercussions in his own life.

:: The Fear Index, by Robert Harris (Cornerstone Digital, e-reader edition around £3.49): Meet Alex Hoffman, a legend among the secretive inner circle of the ultra-rich, who has destroyed a revolutionary system that can manipulate financial markets. Then, in the early hours, a sinister intruder breaches the elaborate security of his lakeside home. So begins a waking nightmare.

:: The Hypnotist, by Lars Kepler, (Blue Door, e-reader edition around £3.99): The best-selling Scandinavian crime writer's latest story sees Detective Inspector Joona Linna faced with a boy who witnessed the gruesome murder of his family. He's suffered more than 100 knife wounds and is comatose with shock so Linna enlists a disgraced hypnotist to help.

:: In One Person, by John Irving (Transworld Digital, e-reader edition around £9.49): This novel of sexual identity sees Billy, the bisexual narrator and main character, telling the tragi-comic story of his life as a 'sexual suspect', a phrase first used by John Irving in 1978 in his landmark novel The World According to Garp.

:: Heft, by Liz Moore (Cornerstone Digital, e-reader edition around £6.07): This gentle tale focuses on the connection between a former academic who weighs 550 pounds and hasn't left his rambling Brooklyn home in a decade and a 17-year-old student who navigates life as the poor kid in a rich school and pins his hopes on what seems like a promising sporting career. The link between this unlikely pair is the teenager's mother, a former student of the overweight academic.

:: Gold, by Chris Cleave (Sceptre, e-reader edition around £8.49): This gripping but heartfelt tale sees cycling rivals and unlikely friends Kate and Zoe competing for a place in the Olympics. One is ruthless, single-minded and seemingly unemotional, the other has a family and a daughter with leukaemia. The story examines the values that lie at the heart of our friendships and the choices we make when everything is on the line.