I defended my PhD dissertation in 1991. It took me forever to finish it but at the end I was at least quite happy with what I had accomplished. I now and then go back and read bits and pieces from it. Always entertaining and sometimes surprising, encouraging or even depressing. The depressing part is when I realize that I wrote everything in my dissertation that I am still working on, and in many cases better than I could write it today (at least it feels like that).
Anyway, I have not had an digital version of the dissertation but found one today (in the Umea University Library). It is in Swedish so it is of course not really readable to many.
A pdf of the dissertation can be downloaded here.