ABSTRACT
The word "change" means "to alter by substituting something for, or by giving up for something else; put, or take another or others in place of to make different, to turn, convert." This is an active process, and what is exciting today are the opportunities we have at every turn to take an active part in our changing world. In public health a great deal of emphasis is given to the concept of planning. Every specialty group places emphasis on planning skills in its standards of training; program planning is one of the basic constructs of education for public health. Ward's provocative book Spaceship Earth provides an image of the world that puts all these massive changes into context. The most important technical change is the development of the computer and the use of cybernetic theory — enabling us to deal in very different ways with the increasing knowledge becoming available.
