Requesting a copy of the PhD thesis from an author? I think that many unpublished theses are available in libraries etc and reading relevant theses is a normal part of research and does not involve asking the author's permission. But suppose a humanities PhD student has seen a thesis title (2008, so presumably in electronic format), that is relevant to their PhD subject and they want to read the thesis but unlike most theses it is not available in the student's libraries or online etc, probably due to the author's geographical location. The author is now a lecturer with a page on the university website. Should the student just email the author and say "Hello I am a PhD student in your field, can I please see your thesis?" Is this a big deal? Are there any do's or don'ts in making this request? 

Thank you...
A PhD thesis is usually a published work, and is normally archived in a university's library. Almost all dissertations are available via reprints. So you could ask your own library how to order a copy of the thesis.

Alternatively, as you suggest, you can contact the author directly. As Anonymous Mathematician suggests in his comment, you can ask for a copy of the thesis, but you should definitely explain why you're interested in the thesis. However, it may be possible—and even more so for a humanities thesis—that the author is currently preparing it for publication, and may therefore be reluctant to share it via electronic means. However, it is just as likely that they're willing to share it.