In the course of the twentieth century science gained insights on the nature of the Cosmos that might have seemed unimaginable even as late as the year 1900. New words and concepts, novel ways of conceiving space and time, and massive efforts to understand the structure of matter were needed to describe the world we were encountering. I embarked on writing this book to gain clearer insight on the factors that had most effectively contributed to all these advances.

Astronomy is a small field whose tools were largely imported from physics and engineering. Early in the century, theoretical physicists provided us with new perspectives for devising and interpreting novel observations.

Then, in mid-century the United States adopted a deliberate policy of coupling basic research to practical national priorities. Other countries followed suit, leading to an explosive expansion of all of the sciences and engineering. Scientific progress led to novel engineering ventures. These, in turn, offered the sciences increasingly powerful research tools. The coupling could not have been more fruitful. For astronomy the benefits were immense.

Today, we may be entering a new era, in which this bond may loosen between astronomy and engineering. Astronomers are turning their efforts to studies of dark matter and dark energy, whose potential utility to society is not at all apparent. In view of competing national priorities governments may find themselves unable to support the development of the novel tools required for conducting such esoteric cosmological searches. Astronomers may then have to find alternative ways of extending their investigations of the true Universe.