What is "timetripper"

TimeTripper is a series of science fiction books by Stefan Petrucha. It follows the minds of Harry Keller, a teenager who can see time itself, and also sometimes Siara Warner, a love interest of Harry's who has helped him through some tough situations.

The series is told mainly from the view of Harry, who sometimes does not understand what is going on, but travels between linear time and A-Time to fix events and outcomes in the lives of others.