A review by theglossreview
Der Quantenzauberer by Eoin Colfer

3.5

A bizarre story! 3.5 stars. 
The quirks of this method of time travel and the flamboyant personalities of the characters are memorable. The plot feels like a hectic, messy rush from place to place, century to century and villain to villain. 
On the downside, violence is completely overused in a meaningless way. There is a severe lack of logic - does time travel create alternate timelines? Is reality changed or has everything “already happened” so there will always be the same outcome? If time travel was possible, would THAT be the best and only use? Why is it so terribly unexplored? (At one point they cite a 99% success rate, but it’s a 50/50 chance.) And the biggest logical flaw: Why would they let a single TEENAGER guard a functioning time machine two thirds of the time? It would’ve been easy to just make an excuse for why Chevie was the only one present AT THAT MOMENT, but she’s on duty as the (almost) sole guardian. 
It’s ironic (but in a funny, good way) that the time travelers just DO NOT CARE in which century they are in. Even the ones set on staying in a certain time do so for practical reasons, not for the sake of living in a different era. They are not deeply moved by being in a different century, nor are they attached to anything in the time they call home. The lot of Chevie and Riley will make you sad. That’s no way for teenagers to live. I hope they get better.