Man of Two Worlds
What would happen if a juvenile alien and a spoiled, power hungry human had to share the same body? And if they both fall in love with the same woman, but with different intentions? When a young alien accidentally steals a ship meant to destroy Earth and all humanity, and crashes it, his only chance for survival is to merge with a human being. His devoted father wants to bring him back, but he and the hierarchy of his race must decide if they can afford to let humanity that threatens them continue to exist, or save this one young alien.
This often comic tale was written by Frank Herbert and his son, Brian; the only such calibration.