You ever look at a book and think its title is too generic?
Roger Zelazny's Wizard World, originally published as two novels, Changeling (even more generic!) and Madwand (not actually generic at all) is a book like that.
Further, "Wizard World" isn't actually that appropriate for the work as a whole. Sure, there's magic and junk. And there are plenty of wizards. But that name just doesn't fit.
Changeling is all about two changelings, one from a world like ours and the other from the world that most of the book's action takes place in (the alleged "wizard" world). Madwand is about the one of them originally from the magical world, as he is a "madwand," a wizard who learned magic without training or tutelage, and is thus (since magic is something of an innate talent to him) more skilled and powerful on average than the typical magic user.
But each book is also about something else-wars between primeval forces. (Spoilers ahead; it's rather inevitable.)
In Changeling, the war is between the forces of technology and the forces of magic. In times gone by, there had been one such war in a time now all but forgotten, and it would seem that this war separated the technology and the magic from each other into two worlds (one of which is clearly Earth or a close counterpart of it). Various forces, including the switch of a magically powerful child from the magic world with a technologically inclined child from the technological realm, resulted in technology reasserting itself in the magic world with that child, eventually an adult, as the focal point. (This probably would explain the character's seemingly magical ability to invent devices far beyond the capabilities of the rest of the area, even before he found the ancient storehouse of technology near where he lived.)
In Madwand, the war is between an older, more magical world and the first magic world. What kind of older, more magical world is it?
Here's a hint: You might meet this guy walking down the street there.
As it happens (and this is a bit of world-building I really appreciate), if the greater magic of the older world were to spill over into the younger one, the magic there would get much, much stronger. On the other hand, it would be proportionately harder to control. In effect? Only madwands, who are rather rare, would be able to use magic in the new world that resulted.
I'd recommend, if you read this book, that you read the two parts in rapid succession. Changeling is rather depressing; Madwand has a satisfying ending. And with that said, I'd also recommend the book itself heartily if you like fantasy that isn't quite in the traditional mold.