“No argument or sermon could be more eloquent for the ecological approach,” wrote Walter Taylor, ESA president in 1935, “than some of these concrete happenings in very recent times,” including “convulsive” changes in species compositions across the Earth; losses of soil and its fertility; pollution of lands and waters; and the global exploitation of and trade in energy supplies, which new modes of transportation had made possible. It was increasingly obvious, he believed, that to counter human-induced transformations of unprecedented violence, rapidity, and scope we needed “a new Declaration of Interdependence” among soils, waters, plants, and animals (including people) that took into account how changes in one place affected other places. What was needed, in other words, was popularization of a more ecological viewpoint. This question of how to convey ecological knowledge to a larger public and its policymakers looms more urgently than ever. With that in mind, symposium participants – scientists delving into their own heritage of ideas and historians exploring ideas of scientists – will bring to life stories of key ecological thinkers who tried to do just that. Speakers will discuss the interplay of historic forces that influenced select scientists’ research, perceptions, and practices of conveying ecological knowledge in response to their growing ecological concerns in the period spanning the coinage of “ecology” to the late 20th century, such as: Victor Shelford (1877-1968) on destruction of ecologically representative “natural areas,” including their native species; Aldo Leopold (1887-1948) on diminishments of land health, including soil and its fertility; Charles Elton (1900-1991) on expansions of invasive species and shifting community relationships; Rachel Carson (1907-1964) on pesticide-related wildlife declines, pollution, and illnesses; and Frank Egler (1911-1996) on managing succession. How did each come to identify particular problems in nature, their causes, and potential remedies? How, why, and with what effect did each attempt to engage the public with relevant ecological knowledge? What impediments stood in the way? Participants also will discuss implications of individual ecologists’ various attempts, their commonalities and differences with the idea of coming to more general conclusions. Finally, the symposium will encourage discussion of how lessons from history might be applied as we try to meet intensifying global sustainability challenges with new ecological knowledge.