Secondary education is the final stage of compulsory education, preceded by primary education and followed by higher education. It is characterised by transition from the typically compulsory, comprehensive primary education for minors to the optional, selective tertiary, 'post-secondary', or 'higher' education (e.g., university, vocational school) for adults. Depending on the system, schools for this period or a part of it may be called secondary schools, high schools, gymnasiums, lyceums, middle schools, colleges, vocational schools and preparatory schools, and the exact meaning of any of these varies between the systems. The exact boundary between primary and secondary education varies from country to country and even within them, but is generally around the fifth to the tenth year of education. Secondary education occurs mainly during the teenage years. In the United States and Canada primary and secondary education together are sometimes referred to as K-12 education. The purpose of secondary education can be to give common knowledge, to prepare for either higher education or vocational education, or to train directly for a profession. This new book presents the latest research in the field.