(Original Review, 1980-11-06)
The most well thought out model of time-travel I have ever seen in a novel was in Hogan's "Thrice Upon a Time". This book ascribes to the "reset" theory of world-lines; if you send a message into the past (no matter travels cross-time in this book but it doesn't seem to be ruled out) that says "kill me, I am about to do something very rude in the present, and I should really be stopped", then the people back then get to act on the information while you wait in the present, with your teeth clenched, for the effects of your message to ripple forward and absolve (dissolve?) you.
If you're into stuff like this, you can read the full review.