Beka Cooper series by Tamora pierce.
I really liked them, i thought that they were great books, though I didn't like the touch of Homosexuality that Tamora put into the second book. Over all they were very good, the first one being my favorite. Tamora does such a great job writing them, and they are a very good series to read. I wouldn't read them if you are under 14, they are for a older audience then most of Tamora's Tortall books.
Over all though, the rise and fall of each book were good, though in the first book she stopped child killers, and mass murder of diggers after an opal vine is found, and in the second it is money forgers. I think she could have made it a little more high stakes, granted that coals in the system is high, but it just wasn't as high of stakes as the first and second ones. And I love the character Farmer. He suddenly appears in the third one and intraduces a strange kind of magic. LO