They’re light, portable, they store hundreds of books and allow you to download anything you fancy reading on a whim.
What’s not to like about your e-reader?
A study by medical teams at Harvard University has found that e-readers could be seriously affecting your health.
People who use backlit e-readers at night take longer to fall asleep than those reading paper books, the research found.
Doctors locked 12 people in a sleep lab for two weeks and studied how long they took to fall asleep depending on whether they read a paperback or an e-book.
When reading the e-book, the subjects took longer to fall asleep and had poorer quality sleep.
It’s all down to how our body clocks work – using light to gauge the time of day.
Looking at smartphones, tablets and backlit e-readers before going to sleep can disrupt our body’s perception of the time and make it harder to fall asleep, according to lead researcher Prof Charles Czeisler.
He told BBC News: “The light emitted by most e-readers is shining directly into the eyes of the reader, whereas from a printed book or the original Kindle, the reader is only exposed to reflected light from the pages of the book.”
Having poor quality sleep also goes on to create bigger health problems, he added.
“Sleep deficiency has been shown to increase the risk of cardiovascular disease, metabolic diseases like obesity and diabetes, and cancer.”
Doctors advised people to avoid using their electronic devices late at night to limit the effect on their body clocks.