A 2-YEAR STUDY OF THE ABILITY OF FIRST GRADERS TO LEARN TO READ USING THE "EARLY-TO-READ I/T/A/" SERIES WAS CONDUCTED. SIXTY-ONE FIRST GRADERS IN ROSE HILL ELEMENTARY SCHOOL, MUKILTEO, WASHINGTON, WERE RANDOMLY ASSIGNED TO AN EXPERIMENTAL GROUP USING THE I/T/A SERIES AND TO A CONTROL GROUP USING THE "GINN BASIC READERS." THREE RANDOMLY CHOSEN FIRST-GRADE CLASSES SERVED AS THE SUBCONTROL GROUP. ACCORDING TO READINESS TESTS, AN INTELLIGENCE SCALE, AND AN ALPHABET KNOWLEDGE TEST, THE EXPERIMENTAL AND CONTROL GROUPS WERE NOT SIGNIFICANTLY DIFFERENT. ABOUT 160 BEGINNING READING TRADE BOOKS WERE TRANSLITERATED FOR THE EXPERIMENTAL GROUP. TRADITIONAL EDITIONS WERE MADE AVAILABLE TO THE CONTROL GROUP. OTHER TESTS GIVEN WERE THE GRAY ORAL READING TESTS, THE STANDARD READING INVENTORIES, AND THE STANFORD ACHIEVEMENT TESTS. RESULTS INDICATED THAT THERE WERE NO SIGNIFICANT DIFFERENCES IN FIRST-GRADE ACHIEVEMENT, IN SECOND-GRADE ACHIEVEMENT, OR IN OVERALL READING ACHIEVEMENT BETWEEN THE EXPERIMENTAL AND CONTROL GROUPS. BOTH GROUPS WERE SUPERIOR TO THE SUBCONTROL GROUP. THE EXPERIMENTAL GROUP READ SIGNIFICANTLY BETTER THAN THE OTHER TWO GROUPS WHEN READING I/T/A MATERIALS AND CONSISTENTLY SCORED HIGHEST. THE SUBCONTROL GROUP CONSISTENTLY SCORED LOWEST. (NS)