While browsing notcot, I came across this book titled "Design Sketching", and I must say they piqued my interest. It is about sketching for industrial design, here is a better description:
Design Sketching
By: Erik Olofsson and Klara Sjölen
ISBN: 91-631-7394-8
The books goal is to to inspire and teach sketching by displaying a broad collection of examples of all the large variety of sketches that are useful in the design process.
Design Sketching
By: Erik Olofsson and Klara Sjölen
ISBN: 91-631-7394-8