In Novik's earlier fantasies (His Majesty's Dragon
, etc.), readers soared to Europe and Asia on the wings of an intriguing premise: How would the Napoleonic Wars have played out if dragons not only existed, but participated in the war effort? The fourth part of Novik's engrossing answer sweeps readers off to Africa, where the cure to the disease that has decimated England's dragon forces may be found. The African adventures of British captain Will Laurence, his dragon Temeraire and their bedraggled band of aerial corps make up the book's latter half, which showcases Novik's knack for weaving dragons and dragon lore into a vivid, well-researched historical tapestry. In Africa's wild interior, dragons shepherd and feed from elephant caravans while protecting the native villagers. This protection includes waging war against England's slave-seeking colonists, a clash that Laurence and his band may not escape unscathed. Novik fills the conflict's lead-up with lengthy meditations on dragon civil rights and England's abolition movement, making for a fitful, pedantic first half. But most will find the richness of Novik's developing world—and characters—to be worthy compensation for the slow start. (Oct.)