Karr (The Great Turkey Walk
) weaves in actual historical facts as her novel takes readers into "Deepest, Darkest Africa," alongside the bombastic writer and explorer Henry Morton Stanley (who famously uttered the phrase "Dr. Livingstone, I presume?"). Sixteen-year-old Tom Ormsby works in a pharmacy in 1880s London, though he dreams of a life of excitement. When he is sent to deliver medical supplies to Stanley, he finagles his way onto the man's latest expedition: a voyage into the heart of the Congo to rescue Emin Pasha, the head of Equitoria who reportedly has been besieged by Islamic Mahdist forces. When they set sail in January 1887, Tom is quickly humbled by his seasickness, his inexperience with firearms, and his first assignment—tending to the 40 donkeys on board. However, he soon proves himself: Tom's pharmaceutical knowledge makes him useful to the expedition's physician, and he convinces the 600-odd Soudanese and Zanzibari porters to get inoculated against smallpox. As the years press on, Tom is catapulted into manhood, as he defends the expedition against frequent native attacks ("Wasn't every day I shot at least five human beings.... Worst of it was, I would've picked off another five if the cannibals hadn't packed it in"), and dissent from within; Tom himself grows disenchanted with his former hero, Stanley. Karr suffuses this coming-of-age story with a wealth of historical detail and a steady stream of action, sure to captivate readers who may harbor their own dreams of adventure. Ages 12-up. (Apr.)