It's a pretty good book, and most of it holds up well even given the ever changing world of technology that we live in today. Heinlein was quite a prognosticator. His stories extrapolated several innovations. He also had an interview in a magazine during which he made some speculations about the near future. Nothing he wrote was accurate enough to make you think that he had a crystal ball, but following trends and making predictions is a difficult task. If it was easy we could all make fortunes on stocks.
Here is a list of items, in no particular order, which he either predicted for the immediate future or incorporated into his novels that have since come to pass:
- First manned rocket to the Moon by 1978
- Synthetic foods
- Commercial rocket travel
- Development of elements greater than 98
- Robotic exoskeletons for soldiers
- Mobile phones
- Answering machines
- Video phones
- The internet
- Urban sprawl
- The cold war
- The collapse of the Soviet Union
- The sexual revolution
It's not exactly scientific, but anecdotally, it's a pretty impressive list, no? Getting back to The Moon is a Harsh Mistress, there is also a reference to Japan having been goaded into attacking at Pearl Harbor. This is an area where Heinein was ahead of his time also because it is an idea which is sadly still not widely accepted.
There are a couple of items I would like to point out where Heinlein was wrong. In the 1949 predictions interview Heinlein stated that Americans would never fight a preventative war. If Americans had to fight they would, but they wouldn't go looking for one. Unfortunately he was proven wrong the very next year starting with Korea and the long list that has followed through Vietnam to today in Iraq, Libya, and now Uganda.
One other area where he overestimated human compassion was during the planning phase of the revolution in The Moon is a Harsh Mistress. The revolutionary party was using children for small jobs, and the protagonist tells how even the warden's goons would think twice before arresting a child. This book was released in 1959, so the greatly foresighted Heinlein, who had such wonderful insights about such diverse topics as those listed above, failed to see how terribly children would be treated in a war less than 50 years way. This was the one part of the novel that made me stop and think to myself how much time has changed.