Foundling

Rossamünd Bookchild (I would so much love to be part of his family) has spent his life in an orphanage, but he's finally been assigned his career—he is to be a lamplighter in a far-away city. He lives in a world with monsters everywhere, and, to defeat them, a great many people have become monster-hunters, and the tattoos in the book title are signs on a monster-hunter of monster kills. There is a lot of machinery with biological origins, and a lot of humans have had biological adaptations surgically added.

Of all the books on the 1001 Children's Books You Must Read list (and there are 1001 of them!) this was the book I was dreading the most. That title. That cover. Neither of those had any appeal for me. But was I ever wrong? This was so good that I'd be willing to break my Personal Reading Code and read on in a series.