A Calculus of Angels

1722: A second Dark Age looms after the devastating impact of an asteroid, unnaturally drawn to Earth by dire creatures who plot against the world of men. Sir Isaac Newton and his young apprentice, Benjamin Franklin, have taken refuge in ancient Prague, seeking the secrets of aetheric beings whose vast powers and new sciences have so nearly destroyed humanity ...yet who may prove to be its last, great hope. But their safety is tenuous, as Peter the Great marches his unstoppable forces across Europe. And half a world away, Blackbeard the pirate leads a party of colonial luminaries back across the Atlantic to discover what has befallen the Old World. With sails a Choctaw shaman whose mysterious connections to the invisible world warn him of a confrontation as violent as it is decisive ...'Masterful...a bravura performance...lavish and thoughtful' - "Publishers Weekly" (starred review). 'Exciting, suspenseful, and beautifully written' - Amazon.com.

What if Isaac Newton had discovered that alchemy works? J. Gregory Keyes has based his Age of Unreason series on an alternate 18th century shaped by a "science" that grew from Newton's discovery of "philosopher's mercury," which "can transmit vibrations into the aether" and thus "alter the states and composition of matter." In A Calculus of Angels, Keyes continues the tale he began in Newton's Cannon. It's a satisfying sequel that nevertheless leaves the reader impatient for the next book.

Two years have passed since the asteroid struck. The weather is unnaturally cold, the skies perpetually overcast. England is devastated, the French government has collapsed upon the death of Louis XIV. Peter the Great, now inspired by the guardian spirit who preserved Louis, has marched his armies westward into the Netherlands and France. In the New World, the abandoned colonists send a delegation including Blackbeard, Cotton Mather, and a Choctaw shaman named Red Shoes to find out what's happened. In Prague, Newton and his apprentice, Ben Franklin, seek to protect the city from aetheric attack. The mathematically gifted Adrienne de Montchevreuil is also back and expanding her knowledge of the mysterious malakim who inhabit the aether and menace mankind.

Keyes creates a very believable mixture of history, fantasy, and plausibly imagined historical characters. Each book has been exciting, suspenseful, and beautifully written. No admirer of alternate history should miss this series. --Nona Vero