This is the second edition of a book which was first published in 1989. The first edition was widely welcomed, and has been used as a tool for policy-makers and practitioners in a considerable range of countries. We were very pleased when Mark Bray expressed willingness to update and revise the book for re-publication, and anticipate that this edition will be as enthusiastically welcomed as the last.

This book must begin with some comments on focus and definition. The title refers to double-shift schooling. In a double-shift system, schools cater for two entirely separate groups of pupils during a school day.