Mortal Engines Quartet by Philip Reeve series
Everything good about this series can be boiled down to two words; simply perfect. Really. Because it is. The setting is about as original as you can get (anyone heard of moving cities before this, raise your hand. No one? Thought so). The characters are interesting (and delightfully imperfect, like Hester Shaw with her missing eye and heart of stone, or the Stalker Shrike, who lacks an actual physical heart yet still manages to have more of one than Hester, at least at the beginning), the tech is astounding (Killer Zombie Robots, airships, and giant lasers of doom. Come on), the writing is extremely clean, pretty much cliche-free (unless they're put in on purpose, usually to illustrate the "future imperfect" trope), and very, VERY real. How real? Let me just say "plot armor" doesn't exist in any way shape or form in it. If there's someone alive in the book, they're killable. And, in the case of at least one character, suitable to be resurrected, and then promptly killed AGAIN. (Most of) the bad guys don't all die at the end, (one even gets off pretty much scot-free!), and really, REALLY bad things happen to good people. All in all, if you love steampunk, you must read this series. If you don't, this is a good place to start. It sure worked fine for me.