Tomorrow we will be launching a competition on Facebook to win a proof copy of The Long Earth. The question, which has been supplied by Sir Terry Pratchett and Rob Wilkins, will be posted on Terry Pratchett’s facebook page. To win the highly rare and prized copy check back on Facebook at 09:00 GMT and email your answer with your name and address to email@example.com. For a hint in this very tricky competition head over to the Transworld blog: What Shall I Read? This competition is open to all readers anywhere in the world. Good Luck!