During the 40 year duration of Walter's professional career as a land use planner and urban economist he has been involved and remained curious about harmonizing our human activities with natural systems, a goal presently referred to as "sustainabilty". Early on in his career as a land use planner it occurred to him that the best lever point for this work was economics. Walter's firm, EPS, focuses on "the economics of land use" including the study of economic impacts of projects and plans, determining feasibility of projects, financing public infrastructure, optimizing government organazation and finance, and conserving natural resources.