Shades of Magic series by V.E. SchwabRead about the other entries on the list.
I, like many others, love Schwab’s take on the multiverse. This series features a finite number of worlds, all four connected by a single fixed city. Grey, Red, White and Black… each version of London has its own personality and only Kell, the protagonist, possesses the ability to travel between them. His magic is a dying breed, however, and the consequences of this become clear when Kell mistakenly smuggles an item that puts every London in peril. The way Schwab parallels these worlds while also pitting them against each other makes for an addictive, exciting read.
--Marshal Zeringue