In the February 1952 issue of Galaxy magazine, Robert Heinlein offered his verdict on the conclusion of the twentieth century. He would later revisit these predictions in the 1966 short story collection The Worlds of Robert A. Heinlein and discuss the challenges of predicting the future. Here's what the author gathered, six decades ago:

So let's have a few free-swinging predictions about the future. Some will be wrong - but cautious predictions are sure to be wrong.

1. Interplanetary travel is waiting at your front door — C.O.D. It's yours when you pay for it.

2. Contraception and control of disease is revising relations between the sexes to an extent that will change our entire social and economic structure.

3. The most important military fact of this century is that there is no way to repel an attack from outer space.

4. It is utterly impossible that the United States will start a "preventive war." We will fight when attacked, either directly or in a territory we have guaranteed to defend.

5. In fifteen years the housing shortage will be solved by a "breakthrough" into new technologies which will make every house now standing as obsolete as privies.

6. We'll all be getting a little hungry by and by.

7. The cult of the phony in art will disappear. So-called "modern art" will be discussed only by psychiatrists.

8. Freud will be classed as a pre-scientific, intuitive pioneer and psychoanalysis will be replaced by a growing, changing "operational psychology" based on measurement and prediction.

9. Cancer, the common cold, and tooth decay will all be conquered; the revolutionary new problem in medical research will be to accomplish "regeneration," i.e., to enable a man to grow a new leg, rather than fit him with an artificial limb.

10. By the end of this century mankind will have explored this solar system, and the first ship intended to reach the nearest star will be a-building.

11. Your personal telephone will be small enough to carry in your handbag. Your house telephone will record messages, answer simple inquiries, and transmit vision.

12. Intelligent life will be found on Mars.

13. A thousand miles an hour at a cent a mile will be commonplace; short hauls will be made in evacuated subways at extreme speed.

14. A major objective of applied physics will be to control gravity.

15. We will not achieve a "World State" in the predictable future. Nevertheless, Communism will vanish from this planet.

16. Increasing mobility will disenfranchise a majority of the population. About 1990 a constitutional amendment will do away with state lines while retaining the semblance.

17. All aircraft will be controlled by a giant radar net run on a continent-wide basis by a multiple electronic "brain."

18. Fish and yeast will become our principal sources of proteins. Beef will be a luxury; lamb and mutton will disappear.

19. Mankind will not destroy itself, nor will "Civilization" be destroyed.

Here are things we won't get soon, if ever:

— Travel through time

— Travel faster than the speed of light

— "Radio" transmission of matter.

— Manlike robots with manlike reactions

— Laboratory creation of life

— Real understanding of what "thought" is and how it is related to matter.

— Scientific proof of personal survival after death.

— Nor a permanent end to war.