I thoroughly recommend Lock & Key by Gordon Bonnet. The characters are three-dimensional, the plot is well-developed, and the settings are rich and tangible. If you love sci-fi, you don’t want to miss this novel. And if you’re new to the genre, this is a great one to start with.
The Many Worlds interpretation, or the idea that every time an event could have gone one of two different ways, it goes both—in different universes. Put another way, when there's a decision to be made, every possible outcome occurs somewhere.