Issues

Current emphasis on studies of very small systems and very short time intervals, on the one hand, and large‐scale objects of astronomical dimensions, on the other, should lead to increasing interaction and unity between them.

Two complementary approaches to strong‐interaction theory, the multiperipheral bootstrap and the dual‐resonance models, appear to be the most promising ways ahead. The idea that emerges is that particles hitherto thought to be “elementary” might instead be composite, all made up of bound states of each other.

In a rapidly growing field computers talk to students, simulate experiments, calculate and perform many special tasks. Problems remain to be solved, but if advantages are exploited and costs reduced, computers should become effective, uncomplaining tutors.

This method is incapable at present of calculating cross sections and is often thought to be obsessively mathematical. Neverthless it offers a conceptual clarity indispensible for understanding the quantum mechanics of systems with an infinite number of degrees of freedom.