In this study, researchers examined the math-related expository books found in 23 first-grade classroom libraries to determine specific mathematical concepts related to counting and cardinality and operations and algebraic thinking addressed in each. In addition, they examined how these concepts aligned with the first-grade Common Core State Standards for Mathematics. Results indicate that most of these texts contained concepts related to counting and cardinality but were better aligned with kindergarten standards than the first-grade standards. Very few of the books contained content related to operations and algebraic thinking and again, those that did focused on content more appropriate for kindergarten students.