Elementary teachers often integrate science-themed trade books into their science and reading lessons. This study examines the alignment of science-themed trade books written for readers in Kindergarten through fifth-grade to the Next Generation Science Standards Disciplinary Core Ideas (NGSS DCI). The goal of this research is to analyze the scientific concepts presented in the text of the trade books recommended by professional organizations dedicated to science and science education. Research finds that integrated science and reading are valuable for elementary students' understandings of science. This study addresses two problems: (1) elementary teachers have limited scientific knowledge and (2) there is a dearth of research that examines the expression of NGSS DCI in science-themed trade books for K-5th grades. The sample is selected from booklists compiled by professional organizations devoted to science and science education. A deductive content analysis methodology is used to identify the presence of NGSS DCI in trade books. Descriptive statistics and qualitative data analyses are used to reveal the themes in the collected data. A large majority of the sample is aligned to the NGSS DCI for K-5th grade. Most trade books express NGSS DCI at the grade levels for which they are recommended. The study is limited and does not examine the readability of trade books, scientific vocabulary, or images. This study contributes to the research on the intersection between science and reading for elementary grade levels. [The dissertation citations contained here are published with the permission of ProQuest LLC. Further reproduction is prohibited without permission. Copies of dissertations may be obtained by Telephone (800) 1-800-521-0600. Web page: http://www.proquest.com/en-US/products/dissertations/individuals.shtml.]