The best reference on the Camino de Santiago.(Rating: 5)
I bought this book in 2003 before embarking upon the Camino Frances. It turned out to be a marvelous multi-faceted reference. Due to weight considerations, I left it at home, instead of schlepping it 800 KM across Spain. Then, outside of Burgo de Ranero, I see THIS BOOK, waiting for me on a roadside bench. "That's my book!", I exclaim. Needless to say, it traveled with me the rest of the way to Santiago. Regardless of weight. If there's only one book you get about the culture, history and architecture of the Camino, this should be it. Buy this book!

I liked it, I liked it ...(Rating: 5)
As is apparent from other reviews in this thread, "The Pilgrim's Road to Santiago: The Complete Cultural Handbook" by Gitlitz and Davidson elicits strong feelings, both pro and con. I personally found this book to be an invaluable reference while walking the pilgrimage route. However, I recognize how other individuals might differ in their assessment.

First and foremost, it is essential to recognize what this book is NOT designed to do.

The handbook is not a trail guide.
It does not list refuges or explain where to camp.
It does not tell you where to eat or what to pack.
If this is what you are looking for, find another book.

With that said and done, the handbook did provide me with an extremely valuable reference in establishing a cultural context for the sites that I was visiting. I am not an expert in Romanesque architecture, nor do I know the lives of Roman Catholic saints well enough to recognize the major figures in a Retablo. I never had the opportunity to extensively study the history of the pilgrimage. Left to my own devices, I would most certainly never have read much in the way of medieval Spanish poetry. In all honesty, even after walking the pilgrimage route, I am still far from expert in all of these areas. However, the handbook did provide me with enough information that I was able to appreciate much more of the sites that I was visiting.

As other individuals have noted, time for sightseeing is often short. I found the handbook to be extremely useful in prioritizing my time and determining which sites would be most interesting to visit. As an example, none of the other sources that I consulted noted the existence of the Blacksmith forge at Compludo which may very well have been my favorite part of the trip. Without the handbook, I would have never have visted half the church nor understood a quarter of what I was seeing.

As I noted at the start of this posting, when it comes to the handbook, your mileage may vary. Each person has their own reason for traveling the Camino. If you aren't interested in cultural history or architectural reference, you might find it more useful to bring another reference. However, if you are interested in understanding the "why" behind what you're seeing, I think that you will find this reference as valuable as I did.

Very complete and entertaining book(Rating: 4)
I was expecting to know something about the medieval heretic Prisciliano but the authors don't mention him. Prisciliano is, according to studies by Victoria Armesto, the real person buried in place of Santiago. Poor old Prisciliano will have to keep waiting in ostracism a little bit longer...

Another thing: The cockleshells that symbolize the pilgrim. The authors don't mention the theory that relates it to the birth of Venus (see Botticelli's work).
Anyway, the book reads easily.

Don't take this to Santiago(Rating: 3)
This book provides a lot of information about the art and culture to be found along the Camino, but it is a totally unpractical guide for those actually walking the 750km to Santiago. First of all it is simply too heavy and bulky to lug around an entire country. Secondly it provides no information on refuges, routes, places to eat, etc. Thirdly the authors frequently recommend staying multiple days at the larger cities, which can be very hard for credencial-carrying pilgrims since most refuges have a one night maximum stay. If you are rich and can afford to rent a car, stay in hotels, and take a couple of months off from work, this is the guide to carry. If you want a more genuine experience I suggest leaving this book at home and picking up one of the many more useful guides upon arrival in Spain.

The Impractical Pilgrim's Guide(Rating: 2)
I purchased this book after reading all of the rave reviews listed here, but don't be fooled as I was! I met many adventurous souls on the Camino, but none who would think to follow the bloated itinerary suggested by these authors. Apart from the lack of maps or accomodation information, some of their trail tips were so off base (i.e. suggestions for scenic detours that wound through industrial land) that I wonder if they even hiked the same path! There are much better guide books out there, but they are not readily available in this country. My suggestion is to wait and buy The Practical Pilgrim's Guide, relatively easy to find in Europe and available in several different languages. I picked up a copy midway through the Camino. While it is much thinner on the cultural and historical details (and thus easier to carry), all points of significant interest are treated with just enough detail, not the kind of overkill that Glitz and Davidson's book doles out. I dumped their book on the side of the road after it gave me its only practical use, as I had run out of toilet paper.