Which resource is essential for tracking children's books, including those from small presses?

The essential resource for tracking children's books, including those from small presses, is "Children's Books in Print." This comprehensive directory provides detailed bibliographic information on books for children and young adults, including title, author, publisher, and publication date. It allows librarians, educators, and booksellers to locate and track a wide range of children's literature, including titles from smaller publishers that may not be listed in other more general bibliographic resources.

In contrast, other options serve different purposes. The "School Library Journal" is a publication that reviews and discusses various books and resources for schools, but it does not function as a complete tracking tool for all children's books. The "EBSCO Serials Directory" is more focused on periodicals and journals, not specifically on children's literature. Similarly, the "Readers Guide to Periodical Literature" provides indexing and summarization of periodicals, which does not pertain to tracking children’s books directly. Thus, "Children's Books in Print" is uniquely suited to fulfill the need for tracking literature aimed at children, making it the correct choice.