“Clarke's Law of Revolutionary Ideas”

Profiles of the Future (revised edition, 1973)
On Clarke's Laws
Source: Profiles of the Future: An Inquiry Into the Limits of the Possible

"Hazards of Prophecy: The Failure of Imagination" in Profiles of the Future (1962)
On Clarke's Laws

Source: Men in Chaos (1942), pp. 23-24

Source: Understanding Capitalism: Competition, Command, and Change, 2005, p.82

Source: Singularity Sky (2003), Chapter 11, “Circus of Death” (p. 234)

As quoted by the New York Times http://www.nytimes.com/2003/10/22/us/luis-a-ferre-dies-at-99-pushed-puerto-rican-statehood.html in an October 22, 2003 obituary.

In both cases the cure is simple though usually very expensive.
"Appendix II: MITE for Morons," The Odyssey File (1984), p. 123
1960s, Clarke's Three Laws, et al (1962; 1973…)

Tactics and Strategy of the Latin American Revolution (1962)
Context: The most submissive countries and consequently, the most cynical, talk about the threat of Cuban subversion, and they are right. The greatest threat of the Cuban revolution is its own example, its revolutionary ideas, the fact that the government has been able to increase the combativity of the people, led by a leader of world stature, to heights seldom equaled in history. Here is the electrifying example of a people prepared to suffer nuclear immolation so that its ashes may serve as a foundation for new societies. When an agreement was reached by which the atomic missiles were removed, without asking our people, we were not relieved or thankful for the truce; instead we denounced the move with our own voice. We have demonstrated our firm stand, our own position, our decision to fight, even if alone, against all dangers and against the atomic menace of Yankee imperialism.

Speech (18 October 1967) http://www.cuba.cu/gobierno/discursos/1967/esp/f181067e.html