I got this book out of the library and decided to give it a go. Not the supernatural improvement mentioned by Noether (possibly due to my half-hearted following of instructions) but quite an improvement all the same.
I would recommend this book to anyone who thinks that drawing is a special talent that only a few have. The book makes it quite clear that its a skill like any other. Once you've finished the exercises in the book you have all you really need to draw pencil sketches. As with any skill, once you learn it, practice makes perfect.