Restoring a book can alter the value of the book, so it is always good to get an idea of your books general value before having any restoration work done on it. I have found these three websites to be helpful:

                       www.ABEBOOKS.com

                       www.Alibris.com

                      www.Bookfinder.com

These sites will give you an idea of what book dealers are asking for your book. I can in no way give you an idea of your books value or whether the restoration will alter that value. You can also contact a local antiquarian book dealer for an appraisal.