How the use of the Primary Language Record (PLR), an authentic assessment of young children's literacy development, has influenced teaching and learning in one New York City public elementary school was studied. The study looked at classroom practices; professional development; student work; and the thoughts of teachers, administrators, students, and families at Public School (P.S.) 261 in Brooklyn's Community School District 15 over several months in the 1992-93 school year. The PLR is a vehicle for systematically observing children in aspects of literacy development using classroom events and work samples. It includes a parent interview and the record of a parent conference early in the year, as well as a narrative report on the child as a language user, comments from the child and family, information for the teacher in the following year, and results of reading scales. A description of one first grade classroom illustrates use of the PLR. The PLR can recognize the diverse strengths and knowledge children bring to the school experience as it supports the professionalism and integrity of teachers and involves parents in the educational process. Experience at this school provides some insights into problems and questions in implementing the PLR. (Contains 18 references.) (SLD)