Fantasy and Sci-fi in one

This series about a young criminal mastermind/juvenile genius is one of the more suspenseful and thrilling series out there. Around every turn there is some new twist, some new plot or evil pixies to overcome. Filled with plenty of humor, sci-fi, fantasy and suspense to go around, this series is one the Bookworm enjoys reading over and over.
  The large cast of characters also helps in this brilliant series. A technical-minded centuar, an evil-mastermind pixie, an elf who the bookworm is having trouble describing as everything it thinks of is either to girly or to manly or to evil (she is not evil by the way), a side-splittingly funny dwarf and the man-giant guard of Artemis's every step. These  characters fill these pages, following Artemis as he plunges into adventure after world-saving adventure.
  The bookworm definitely recommends this series, and is going to go reread the last book this very moment.