Irreverant, playful and based, at least in part, on the lives and work of two great German scientists, this witty bestselling novel skips from Berlin in 1828, when Alexander von Humboldt and Carl Friedrich Gauss meet as old men at a scientific congress in Berlin, to youthful Humboldt's travels in the Orinoco and Ecuadorian Andes.  (GER202, $14.95)