The studies which comprise this report are as follows: (a) Document 1, Development of the Matrix Test by Herbert Zimiles and Harvery Asch (PS 001 072); (b) Document 2, Studies of the Social Organization of Head Start Centers by Donald Horton and others (PS 001 073); (c) Document 3, An Experimental Approach to Studying Non-Verbal Representation in Young Children by Margery Franklin and Judith Cobb (PS 001 074); (d) Document 4, Development of Observation Procedures for Assessing Preschool Classroom Environment by Virginia Stern and Anne Gordon (PS 001 075); (e) Document 5, Comparative Item-Content Analysis of Achievement Test Performance in Young Children by Herbert Zimiles and Stephen Silk (PS 001 076); (f) Document 6, Individual Instruction Project 1 by Renee Reens and others (PS 001 077). (BO)