An very good first Newnes edition copy with dustjacket of Malcolm Saville's Man With Three Fingers (1966) is around £100 to £120. I have resisted paying out silly money and have contented myself with the abridged Collins edition. Even tatty reading copies at reasonable have not been available when I looked. I was delighted to find a copy with dust jacket for £40 described as Acceptable only because it is 'cocked'. It arrived this morning. I would described the dj as Good to Very good - a very good dj without book was selling last week for £60 so I could probably ask £40 for this dj alone.
The book inside I would also describe as Very good, except for the cocking.
So what is cocking, and can you uncock a book? Here is a photograph of the cocked spine. What happens is that the book is read many times until the spine becomes mis-shapen.
What you have to do is pretend that you are reading the book back to front. Turn the back cover to become the front, and go through page by page rubbing your thumb up the central crease. Here is a photo of the same book that has been given this treatment once (sometimes you need to do it twice).
So, the book is uncocked and I could sell it on at twice the price. It took 2 minutes.