This is another old novel, probably from the 1960's or 70's. Earth is at war with a race of giant (really giant, like 50 feet or more) human-like aliens. We retrieve one of them that was injured, brain-dead but otherwise undamaged. This gives us a weird opportunity to spy on the aliens. One of the alien's eyes and part of it's brain are cored-out to make room for a capsule with two humans, a man and a woman, so they can spy on the aliens. I remember there were some rather "adult" scenes with the man and woman. I think it may have been written by a British author. Can anyone identify this book?
The Mind Behind the Eye by Joseph Green. Published in 1972 by DAW Books.
In Britain was it titled "Gold the Man," published by Gollanz in 1971.
Gold [a genetically enhanced man] lives in America, in a world governed by the United Nations. Humanity has been under attack by an extra-terrestrial race they know only as Exterminators, having never seen an individual. The conflict has resulted in one of the enemy ships crashing on the Moon. The sole survivor is a humanoid giant, who was brain-damaged due to lack of oxygen.
The Russians also have a genetic superman, Pavel Petrovna. He has built a capsule inside the giant's head, with the ability to control its body's movements from a keyboard while observing the world through one of the eyes. Petrovna himself is deformed, with arms and legs too short for his body. Only Gold has the ability to operate the controls. The plan is for Gold and Petrovna to be installed in the capsule inside the giant, and await rescue. The giant will taken back to his home world, allowing the humans to gain intelligence about their attackers.
Things don't go as planned and Petrovna is replaced by his assistant, Marina Syerov.