Summary: Originally published in the Italian,Constraints and Possibilitieshas caused a considerable stir in Europe and has already been translated into several languages. In what noted cyberneticist Heinz von Foerster called a stroke of genius, Ceruti applies a new perspective to our understanding of evolution, and startlingly outlines how the evolution of our knowledge and our knowledge of evolution have in fact been mirror images of each other. Expanding on the intellectual tradition of Gregory Bateson, Ervin Laszlo, Stephen Jay Gould, and Niles Eldredge, Ceruti's work is a testament to the paradigm shift occurring in science today. Indispensable reading for anyone interested in the evolution of our conception of knowledge.