"The alliance of three alien races against interstellar humanity, the defection of a human military scientist, and the signs of an impending war call for desperate measures from the Colonial Defense Forces. The creation of the superhuman hybrid Jared Dirac from the DNA of the traitor Charles Boutin is intended to provide a window on Boutin's mind and on the reasons for the alien alliance, but the transfer apparently fails, and Dirac is assigned to the Ghost Brigades, Special Forces troops cloned from the DNA of dead men minus any moral qualms. The sequel to Old Man's War combines taut military action with keen insights into the moral issues revolving around developing technologies. Scalzi has a finely tuned sense of balance between personal drama and the ‘big picture’ in this SCI FI Essential Book choice. Highly recommended."—Library Journal (starred review)

"Scalzi's riveting and original Old Man's War introduced readers to the Colonial Defense Forces (CDF), an Earth-based galactic army composed of senior citizens rejuvenated by high-tech wizardry into youthful warriors. In this equally engaging, battle-driven sequel, the CDF's latest operation entails tracking down renegade scientist Charles Boutin, who is responsible for handing over deadly military secrets to humanity's extraterrestrial enemies. Fortunately, a computer-based replica of Boutin's consciousness is on file and ready for transfer into newly cloned special-forces soldier Jirad Dirac, who shares Boutin's DNA. When the consciousness transfer doesn't quite take, Dirac is handed off to a battalion for routine but closely monitored training. Just when Dirac is getting comfortable with his own identity, however, Boutin's memories kick in, and Dirac and his team are summarily dispatched to an enemy planet to capture Boutin and solve the mystery of his treason before humanity is destroyed. Scalzi skillfully weaves together action, memorable characterizations, and a touch of philosophy in a first-rate military sf outing."—Carl Hays, Booklist

"[A] fast-paced interstellar military drama . . . It follows Jared Dirac, a superhuman soldier, from unusual birth to ambiguous death. Dirac is an altered clone of Charles Boutin, a military scientist who betrayed humankind to alien aggressors, and the Colonial Defense Forces' only hope of finding Boutin lies in transplanting his memories into Dirac's brain. When the transplant seems to fail, Dirac is sent to Special Forces, known as the Ghost Brigades for their habit of creating new soldiers from the DNA of the dead. His indoctrination there comes in handy when Boutin's memories begin to surface. Scalzi pays gleeful homage to Ender's Game, The Forever War and Starship Troopers."—Publishers Weekly