ROCKET and ramjet engines have not the universal application that gas turbines command and possibly on this account they have not had, until recent years, the development effort which gave such amazing results in turbine powered aircraft. Nevertheless, they have demonstrated quite dramatically in various parts of the world that they are power plants to be reckoned with. In Great Britain, their value for aircraft was appreciated somewhat belatedly and events have since decreed that the promise they showed should be smothered before it could become a vital fact. On the other hand their importance for missiles was realized at the conclusion of the 1939–45 war, but again they were not encouraged on anything like the scale that present events show would have been justified. Because of this lack of encouragement, British rockets and ramjets, instead of leading the world, as do gas turbines, are struggling hard to provide a modest rate of progress.