The Necromancer by Michael Scott

Quick -- think of a major figure, hero(ine) or villain, from history. Chances are good that Michael Scott has a place reserved for them in his Secrets of the Immortal Nicholas Flamel series. From Billy the Kid to Quetzalcoatl to Joan of Arc, they're all here, and they all seem to believe that teenage twins Josh and Sophie are the key to the future of the world. If it all seems a little improbable, that's because it is. But Scott keeps the action going at a great pace, with explanations along the way as events get more confusing. This is obviously not the end of the series, but it would be nice to see an ending to the book that doesn't just lead to an obvious next chapter. One bit of trivia: you can read about John Dee, Elizabethan man of science and astrology (and possibly espionage), in both this book and Maria Rutkoski's Celestial Globe. What fun!