Time Split Series by Patricia Smith
Time Split #1
Time Split
Patricia Smith
A scientist is working on teleportation when he accidentally produces a time machine. Initially, he vows to never use the machine to go back in time, but finally relents when he decides he could use it to help his mother. He goes back to Germany, just before World War II, to carry out a 'harmless' tinker, but when he returns to his own time zone he finds a world ravaged by global nuclear war.
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