<P>Nicholas Georgescu-Roegen''s (1906-94) most original contribution is his bioeconomic theory. Based on a profound rethinking of the foundations of neoclassical economics, bioeconomics represents a completely new paradigm compared to both the standard and the Marxist approach. Opening economics to natural sciences led Georgescu-Roegen to point out the bio-physical limits to growth. In the last years of his life, he also criticised the sustainable development paradigm, but his criticism disappeared together with him, only to re-emerge recently, thanks to the research on his archiveand to the interest for his viewpoints within the framework of ''degrowth''.</P><P>In his last years Georgescu-Roegen intended to publish a text entitled <EM>Bioeconomics</EM>, as an initial systematic arrangement of this doctrine. This book aims to pick up that project in two ways: first, collecting Goergescu-Roegen¿s main contributions to bioeconomic theory, some still unpublished, and tackling the pri