The latest editions of Holt science textbooks may be purchased directly from the publisher at HMHco.com. Copies of older editions are often available from online sellers such as Amazon.com, Textbooks.com, or DirectTextbook.com.
The Houghton Mifflin Harcourt website provides a search engine that can identify Holt science textbooks based on grade, state or topic. The company sells textbooks for both classroom and home use. Supplemental materials for home use are limited, but some student workbooks are available. The site includes a Family Learning Center section with links to educational apps and printed resources that can be used in conjunction with textbooks used for home study. Holt McDougal is a division of Houghton Mifflin Harcourt Education Services.