Abstract  Ecology teaches us that all things are related, whereas human ecology focuses on the interrelationships of human beings and of human beings in their environments.  Studies by world systems theorists lie within that large framework, and focus on two major themes of direct interest to human ecologists:  analysis of historical data to predict, and issues related to power.  The scholars who call themselves world systems theorists study, examine and analyze historical data, including information on the economy, in politics, and on related areas, to try to understand the past and predict the future.  A second arena concerns the gathering up, holding, and use of power, illustrated for example, by economic and political decision-making and decision-makers.  Power, of course, defines those with the strength and position to make and enforce decisions that affect others, that is, a core and a periphery.  Human ecologists can generate important studies and focus their analyses by becoming more acquainted with the concepts and approaches of world systems theorists.