William H. Sadlier, Inc. William H. Sadlier, Inc. (SADL) is an educational publishing company that develops and distributes print, digital, and online materials for K-12 public and nonpublic schools as well as catechetical resources for Catholic schools, parishes, and families; its core school offerings include mathematics programs, English language arts curricula such as reading, grammar, writing, vocabulary, phonics (e.g., From Phonics to Reading), and intervention tools, while religion products encompass catechetical programs (e.g., We Believe: Living Your Catholic Identity, Christ In Us), sacrament preparation (bilingual options available), lifelong learning resources, professional development, and virtual events. Founded in 1832 and headquartered at 9 Pine Street in New York, New York, the company serves educators and students across the United States and international markets through sales representatives and distributors, focusing on research-based content that supports academic achievement and faith formation. In October 2024, William H. Sadlier, Inc. partnered with Archangel Education and Technology to integrate innovative classroom devices, IT management, and ISO-certified services with its programs for enhanced student engagement; it also collaborated with Littera Education to deliver personalized virtual tutoring aligned with its science-of-reading phonics program.