Give an extra copy of your thesis to the examiner(s) after the examination

Reserve an extra, pristine copy of your book for the examiner. The examiner's copy is a working copy: they will read it carefully, jot lots of comments to its pages, tear pages, glue post-its to it, use paper clips to mark pages, etc. because they have to. No one can thoroughly understand a thing as complex as a doctoral thesis without memory aids like these. And examiners have to understand the thesis thoroughly.

It is a thoughtful and polite gesture to hand a clean copy to the examiner after the examination. If you sign it, and write a few words to it, it also becomes a nice personal memory for the examiner.