24 Pa. Stat. § 8-803
All school textbooks, in school districts of the second, third and fourth class, shall be adopted by the board of school directors at any regular meeting. Such books, so adopted, shall be provided for the use of the schools at the beginning of the school terms next following. If in said school districts there shall be a district superintendent, such district superintendent shall report in which subjects new textbooks are needed, and after consultation with the teachers under his supervision, what textbooks should be adopted or changed. No adoption or change of textbooks shall be made without his recommendation, except by a two-thirds vote of the board. Books, supplementary to textbooks regularly adopted, may be adopted and purchased for use in the schools at any time. Such supplementary books shall be adopted in the same manner as textbooks are herein required to be adopted.
24 P.S. § 8-803