Textbooks approved through the provincial evaluation process will normally be retained in the Trillium List for a period of five school years following the date of their initial listing. While the majority of textbook titles in this Purchase Period Expired list have completed their five-year approval period, some titles have been placed in this list because they do not support the relevant revised curriculum policy documents; these are identified accordingly. Textbooks removed from the Trillium List and placed in the Purchase Period Expired list may be used for two school years following the year in which their listing expires. School boards are responsible for ensuring that expired titles are not used as textbooks in their schools after this two-year period.