An okay, but dry, bit of hard sci-fi. As most of us know, Col. Steve Austin is a former Apollo astronaut and test pilot, terribly maimed in an experimental aircraft crash. Caidin goes to great lengths to explore the psychology of such a person. But for some reason, Austin never directly narrates his own feelings or thoughts. All this information is filtered the secondhand point-of-view of Rudy Wells, one of Austin's doctors. We also get a lot of old fashioned early 70's sexism and very unenlightened attitudes towards disability. Before the option of replacing Austin's legs and arms with bionics is raised, everyone just assumes that his injuries make him useless and pitiable. All the characters agree that he would be better off dead. At one point Austin attempts suicide to try to escape the "hopeless" fate of living as an amputee, and this is presented as "courageous." Even though he has PhDs in engineering and history and assorted other degrees, there's no consideration at all of the idea that even with his disabilities, Austin could continue to make great contributions and have a fulfilling life as an engineer, professor, or mentor to other astronauts. If he's disabled, his life is over, according to this book. I'm sure it reflects the prevailing attitudes of the time, but the ableism is just as shitty as the sexism.
Caidin also goes into some technical detail regarding the bionic limbs themselves, and the process of integrating them into a living person. I personally found that interesting, but I can definitely see how a reader expecting more of an adventure story would find that section dull. In a passage that seems quaint from a modern day viewpoint, Dr. Wells explains the amazing new surgery called a "heart valve replacement." While we are still not to the point of creating bionic limbs indistinguishable from the originals, heart valve replacement is something almost routine- if the story was written today, the characters and the readers would not need this kind of detailed explanation.
Once Austin is tooled up and and gets his head straight, the secret government agency that pays the bills sends him out on a couple secret missions. They are bog standard Cold War spy thriller sequences. Austin infiltrates a secret Soviet submarine base, and steals a new model of MiG fighter that the Soviets and Egyptians have deployed in the Middle East. Austin's new bionic legs save the day, but these action sequences are never more than mundane. The second half of the book trys to shows us a more of Austin's point of view, but it turns out he's sort of uninteresting. He never gives any meaningful insight into what it means to be the world's first cyborg. Just a lot of karate chops and wandering in the desert until they get rescued by Israeli helicopters.
The premise is interesting. I can see why it was adapted into the "Six Million Dollar Man" TV series. However, Caidin's writing style is the dry detached prose beloved of hard SF writers of the sixties. That's not really my favorite style of storytelling, so I think that, along with the old-fashioned attitudes, is why I never warmed up to this book.