The Apothecary, Book 1

This book could serve as a launch pad for further investigation into chemistry, biology, physics, the history of the Cold War, Latin, Greek, the differences between the British and American educational systems. And because it's all seen through the often-incredulous eyes of teens caught up in a grand adventure, the subject matter seems intriguing rather than deadly.

The title character, kindly apothecary Marcus Burrows, who turns out to be considerably more than an mild-mannered London druggist, is a formidable force for good, both when it comes to protecting his son and when it comes to saving the world. There are other heroic members of his group, as well. Janie and Benjamin are loyal and brave, and also possessed of good critical thinking skills -- by the end of the book they've learned quite a lot, including a new appreciation of their parents.  While Janie's parents have a ditzy Hollywood quality that doesn't seem quite so fun now that their politics have more or less forced the family to flee their home in the dead of night, it is also quite clear that she and they would walk through fire for each other, and they all know it.

Happy, innocent kissing. Also flustered consideration, amid dire peril, of the practical challenges of maintaining modesty while bathing naked in an invisibility potion in the presence of the opposite sex.