Two Hundred and Fifty Five Shades of Grey

A handsome protagonist. A naive and beautiful young woman. A forbidden romance. A good deal of erotic prose. This book has none of it.
The volume before you contains one page for each shade of grey from RGB255 to RGB1. It's almost certainly the most useless book you'll ever see. If, for some reason, you do need a book with a slightly different shade of grey on each page, then it's inestimably useful and you should purchase it at once.
Alternatively, if you just want a joke gift or something to mildly amuse your friends, purchase it too, or even better, purchase two!