"Tsuba Shusei" by Nakamura is an amazing book with more than 2200 pictures of tsuba. If you are looking for a reference source to learn what province, School or category your tsuba is than this might be the best publication for that. Downside of this book is that it is only in Japanese and pictures are not highest quality.
There is a lot of foxing and passage of time is well visible on this copy. There are no major damages. Please see the pictures.