I have just bought a number of books, whilst waiting for the right moment to start on Penrose:The road to reality, I just noticed that the book appeared to be wishing me to open at a random page?..thus I did this just to see what page it open's at. The page I happened to open at contained a little square piece of paper, with a bar-code? Checking the bar code with the actual book on the back cover, they do not match? I am presuming that the paper is an actual 'security' tag inserted into the book, when I examined it closely it has a 'circuit' foil like quality, but then again the other six book I purchased the same time had no such thing contained within any of their pages. Does any know if this is such a devise, if devises are actually placed into book pages?..seems a bit far to go for security, unless the book contains a National Security risk P.S tha other books are out of interest: The New Quantum Universe by Hey and Walters. Dr Riemann's Zeros by Karl Sabbagh. Faster than the Speed of Light by Joao Magueijo. Einstein Relativity... Routledge. Schrodinger's Kittens by John Gribbin. and to complete my collection on Feynman:Lost Lecture and :Six Easy Pieces.