The Dangers of Computerization
Neumann is not technically fully computerized; he is robotic, mechanized, and his human body is gradually substituted for a mechanical one. He is literally a robot soldier and the last part of this metamorphosis is the uploading of his brain onto a computer. The novel does not come out and state that this is a cautionary tale, or that it is intended as a warning, but it nonetheless is, as the gradual descent into obsession with mechanizing everything.
Military Injury
One of the sub-themes is the need for cybernetics within the military and the terrible injuries that soldiers endure. Neumann is a brilliant engineer and managed to create prosthetics that were almost identical to the soldier's lost limb. The novel highlights the fact that there is a constant need for these prosthetics and also the way in which the military approaches the research into assisting their wounded veterans after injury.