Synthesis of the lifetime genius of Odum as seen through his own words and those of his students, many of whom today apply his ideas to the world in diverse ways. The work traces the development of Odum's ideas with the objective of providing the conceptual and research history that has led to his far reaching ideas about making decisions. It is organised along the chronological path that Odum followed, from ecology to ecological engineering to ecological economics and his controversial synthesis - `emergy analysis'.