Warning: Time Travel is a Serious Business. Do not attempt to alter the timestream without proper training and a good lawyer.
ChronoLaw: A Guide to Time Travel Legalities Temporal Powers: The Ultimate Guide to Time Travel AbilitiesBut wait, what's the point of time travel if you can't mess with the timeline?
The Grandfather Paradox: A Classic Time Travel Mishap Predestination: When Time Travelers Get Too Comfortable