This is a journey by public transport which book lovers will not have any objections. Some trains on the Beijing metro lines four and ten were turned into a kind of library, although it will still be difficult to actually read any of these books in paper edition. This library is actually a kind of advertisement for an application for listening to audio books. If travelers want to listen to audio books that are on offer they have mobillnim their phones to scan some of the codes that are found all over the cars. Once scanned, the codes allow downloading applications through which users can listen to books. This service is completely free. Perhaps this book and on the walls are not straight, but leave a good impression.