Defensor Santiago wrote at least 30 books, many of which are about law and social sciences. Among her works is the "Code Annotated Series Project 2000", a series of books about laws passed by the Philippine Congress and Supreme Court decisions. The "Code Annotated Series" is the main part of Defensor Santiago's Legal Outreach Program. During her initial battle with cancer, she continued to work on the 2014 edition of all her law books. These were published as the 2015 edition of her "Code Annotated Series", by Rex Bookstore.