I know many others have mentioned the book by Tinkler & Jackson before, and I am sure it is not the only useful one out there, but I have just read it and with my viva coming up at the end of May, I now feel better prepared and a bit calmer + knowing what to expect. I am sure most of you know stuff about vivas from friends, supervisors, from this forum etc and might not find this book a massive revelation, but I reckon that most people can get something out it and it reads quickly.
Anyway, I just wanted to recommend the book to anyone who is coming to the end of the PhD, with the viva coming up and ahead of them.
Penny Tinkler & Carolyn Jackson
The Doctoral Examination Process - A Handbook for students, examiners and supervisors
2004
Open University Press
:-)