"This book is an introduction to a recent development in the art. It concentrates on the background, the theory, and some of the implications of these developments. Beyond a brief example here and there, it does not attempt to study particular works, sketching out, instead, an overall view. In the near future, analyses of individual artists will be possible, but not before the nature of the work done is defined and made familiar. The book, further more, is not intended to be a summary after the fact. It has been written in the midst of young activity, with an interest that was both observant and highly biased. Being part of the activity, I was inclined to look at and judge an art-in-the-making as well as influence its course. Artists, like critics and historians, make the history they reflect, even with the best of intentions to remain objective. I thought, when I began writing, that I should try both to observe and to influence as much as possible..." (dalla prefazione)