The 1998 NAEP (National Assessment of Educational Progress) state level reading assessment measured public and nonpublic fourth- and eighth-grade students' reading proficiency in situations that involved reading for three purposes: reading for literary experience, reading to gain information, and reading to perform a task (grade 8 only). This report describes the reading proficiency of Arizona fourth- and eighth-grade public school students, and compares their overall performance to students in the West region of the United States and the nation (using data from the NAEP national assessments). Nonpublic schools at grade 8 failed to meet minimum participation guidelines for reporting. The distribution of reading results and reading achievement level results are provided for subpopulations of students (gender, race/ethnicity, students' reports of parents' highest educational level, free/reduced-price lunch program eligibility, and type of location). The average reading proficiency of fourth-grade public school students in Arizona on the NAEP reading scale was 207 compared to 215 nationwide; and 261 compared to 261 nationwide for eighth-grade public school students. (RS)