Following its initial development in the 1920’s and 1930’s, by mid-century the concept of “levels of organization” began to disperse throughout the life science textbook literature. Among other early textbooks that first applied the levels concept, Eugene P. Odum’s usage of the notion in his textbook series Fundamentals of Ecology (and his later series Ecology) stands out due to the marked emphasis placed on the concept as a foundational, erotetically-oriented organizing principle. In this paper, I examine Odum’s efforts toward advocating (...) the levels concept in ecology in light of the concept’s wider uptake in biology around that time. (shrink)