The English Language and Concepts Program for Spanish-Speaking Children (LCS) is designed to enable Spanish-speaking youngsters to succeed in the regular school classroom. This report presents detailed summaries of major studies in the LCS tryout and evaluation sequence. (1) LCS prototype tryout, 1969: Tryout is described, materials and procedures are identified and pupil test results presented. (2) LCS component tryout, 1970-71: 135 LCS lessons were tested, pupil and teacher feedback obtained and two variants evaluated. (3) LCS product tryout, 1971-72: Materials and procedures were tried; test results, teacher comments and pupil attendance records are presented. (4) LCS classroom observations, 1971-72: Observation procedures and data collected during the tryout are described; implications for revisions are discussed. (5) Development of LCS assessment measure, 1972: Design and construction of this measure are described. (6) Development of LCS placement procedures. (7) Follow-up of participants, 1973: Results indicate pupils' subsequent success in regular English classrooms. (8) Tryout of LCS training system, 1972-73: Reactions of trainers and teachers and later system revisions are described. (9) LCS quality assurance data, 1972-73: Summaries indicate high levels of LCS-instructed pupil performance. (10) LCS quality assurance data inquiry, 1973-74, confirms the program's effectiveness after commercial distribution. (CHK)