What if you knew, from almost the moment you were conscious, the exact and precise reason for your existence? Would it be helpful or would it be a limitation? And how would free will--the ability to choose--be manifested in this circumstance? These are some of the questions explored in The Ghost Brigades, by John Scalzi.

In Old Man's War, Scalzi created and explored the Colonial Union and the Colonial Defense Forces (CDF), which recruits aging humans from Earth on their 75th birthday to become soldiers trained to defend CU colonies. Within the CDF is a group of Special Forces soldiers nicknamed “The Ghost Brigade,” because they are created from genetic materials collected from recruits who died before their enlistment was completed. Unlike the 75-year-old “realborn” forces, Special Forces soldiers are rapidly grown without consciousness and then instantaneously educated and integrated into platoons via the use of a “BrainPal,” an implanted device that allows for the rapid transfer/exchange of information between individuals within a platoon. The result is a fully grown, incredibly powerful, primarily biological fighting machine. These soldiers have no previous experiences from which to judge situations. Their ethics are defined by the education the CDF has uploaded, and their temperaments are infantile, since—chronologically— that’s what they are. And they are deployed within a few weeks of being born!

This novel follows Special Forces Private Jared Dirac, who has been created for a special purpose: to locate and apprehend a potential traitor to the Colonial Union. The state of the Colonial Union, and possibly the fate of humanity as a whole, rests on Dirac’s ability to successfully acquire his target.

The Ghost Brigades successfully expands and deepens the world created in Old Man’s War. Some facets of the universe are expanded, while other are brought into much sharper focus. In addition, The Ghost Brigades explores some interesting issues regarding how, exactly, a person is defined; duty and purpose vs servitude; and what constitutes consciousness at a species level. The result is an intriguing novel that is both enjoyable and incredibly thought-provoking. Like Old Man’s War, the setting is primarily military, including some harrowing battle scenes. While this may be a hindrance to those readers who are uninterested in military science fiction, these factors are worth wading through to explore the larger issues posed in the book.