This document provides baseline information about temporary facilities as alternatives to school construction. More than 40 individual school districts in 18 States cooperated in a review of their units. The study scans the problem of temporary facilities historically, analyzes prevailing conditions at the beginning of the 1960's, makes projections concerning future use of relocatables, discusses new developments and transportation problems, and includes guides for calculating costs. The publication includes a detailed chart that displays specifications for and costs of the temporary structures in 23 selected districts. The chart is keyed to photographs and descriptions of some of the district units surveyed in the study. The document concludes with sketches and plans for a"convertible classroom/commons core" -- a permanent structure designed to serve multiple purposes in conjunction with linkage provisions for a variable number of relocatable units. (Photographs may reproduce poorly.) (MLF)