Letter of introduction for Dwight B. Heard on the arrival of National Park Service Director Stephen T. Mather to Phoenix. Mather's visit includes trips to Roosevelt Dam and Tumacácori.

Provides an overview of Pima County's (1) natural, constructed and administrative form makers, (2) the origins and implementation of planning and zoning legislation and regulations, and (3) a decade-by-decade review of some of the major land use decisions made within Pima County since the 1920s.