The Really Great Reading materials for grades K-2 partially meet the expectations for alignment to Common Core State Standards and research-based practices for foundational skills instruction. The materials have a sequence for explicitly teaching all 26 uppercase and lowercase letters. However, there is no explicit instruction in letter formation. The materials contain explicit instruction in phonological awareness and have multimodal/multisensory opportunities for students to practice phonological awareness skills frequently. The materials contain explicit, systematic instruction in decoding and encoding phonics skills in isolation. The materials frequently allow students to decode words in decodable phrases, sentences, and passages. For grades K-1, there is a sequence for the explicit instruction of high-frequency words. Decodable passages in Grades K-2 contain high-frequency words, although the high-frequency words do not necessarily align with the sequence. The materials do not contain explicit instruction in rate, accuracy, and expression. However, students have frequent opportunities to practice fluency with phrases, sentences, and passages. The Really Great Reading materials for Grades K-2 partially meet the expectations for implementation, support materials, and assessment. The materials contain a well-defined teacher’s manual as well as supplemental resources. The manual and supplemental resources contain instructional routines and adult-level explanations. The content of the materials can be taught in a school year, although the materials do not include instructional timings for activities. The materials contain a clear, cohesive hierarchy for phonological awareness skills, and they contain a scope and sequence for phonics with a general research-based explanation. The materials contain decodable passages aligned to the phonics’ scope and sequence. However, the decodable passages do not align with the scope and sequence of the high-frequency words. The materials have assessment opportunities for some foundational literacy skills, such as phonological awareness and phonics. The materials contain some resources to support multilingual learners, specifically Spanish resources. The materials contain options for differentiation within lessons. The materials contain digital materials compatible with many platforms and operating systems. Some materials can be personalized and customized.