Probably you've gotten tired of these library challenges by now. Well, my answer to that is... too bad! I still have some left, so enjoy them while they last :P. 'Favourite Books'. Pretty boring, hey? Not if you add 'in Codes' to the end! My favourite type of code is concealing my three favourite series, so ask yourself: are you up to the challenge?
Mystery and codes show up frequently in book plots and ideas, so why not twist it around and make you do some work to figure out my favs? Even if you've been a cheater and looked at my favourite books list, have some fun using your inner detective.