The prize
The best five answers will win a copy of the Royal Society Winton Prize for Science Books 2012 shortlist and two tickets to the award event and the after-party, held at the Royal Society.
How to enter
The competition will be run from our Twitter account from Monday 19 to Thursday 22 November.
To take part, simply send a tweet with your answer to the following question: 'What's your favourite science book that you've read this year - and why?'
Please include the hashtag #SciBooks in your answer so that we can find it.
The entries will be judged by Tania Hershman, a member of the prize's judging panel. She'll pick the winners based on originality and creative use of Twitter's 140 character limit.
No purchase necessary. You may alternatively enter by sending your answer to Book Prize Twitter Competition, Science Communication, The Royal Society, 6-9 Carlton House Terrace, London SW1Y 5AG by the closing time.
More information
The competition will open on Monday 19 November at 10:00am GMT and will close on Thursday 22 November at 4:00pm GMT.
The competition is only open to UK residents aged 16 or over. You may make as many entries as you wish.
By entering the competition you consent to the Royal Society publishing your entry on our website, on Twitter, at the award event and elsewhere. We will credit the winners' name or Twitter handle where possible.
Tania Hershman will pick the five winners from a shortlist of the entries. The winner will be announced on Friday 23 November and will be notified on Twitter.
Winners will be provided with two tickets to attend the award event and after-party.
Unfortunately no contribution towards travel expenses or accommodation costs can be met by the Society.
Winners who are unable to attend the event and after-party will be sent the shortlist by post.
The competition is run by the Royal Society and the final decision about its outcome is made by the Royal Society.