The Sign of The Four will be used in the third series of BBC Sherlock as The Sign of Three. I'm quite thrilled that for once I have read the book before they used it, and I will be able to look for everything they used form the book. I can't wait till the third series start!
I liked reading this book as well. The writing style is still quite modern, and reads very easily. The story itself is quite interesting, so it was really a nice read.