The Parker "51" book by David and Mark Sheperd is a wonderful reference book on the pen. It is extremely in depth, as well includes a lot of little facts and rarely seen pictures of the production.

One of the more interesting parts I found in the book was the prototyping section. There are tons of pictures and information you would have probably never known about the Parker "51". One of the more interesting things I found out involved the variety of nibs that the "51" was tested out with. I would have loved to have tried some!

This book is good for the novice and professional pen collector. For the novice there are lots of fun pictures to look at and pens to dream about getting. For the professional there is probably some information they didn't even know about. I highly recommend this book to anyone who is interested in Parker products!