Unlock is a five-level academic skills course that combines carefully scaffolded exercises, a comprehensive approach to critical thinking and motivating video. Unlock Reading and Writing Skills Level 4 provides 60-90 hours of classroom material. Access to the Online Workbook is provided via a code packaged with the Student's Book. Critical Thinking sections give students frameworks to formulate their own opinions and express themselves effectively in the end-of-unit academic tasks. Unique research into common learner errors (using the Cambridge English Corpus) focuses the language used in Unlock on those areas learners find most challenging. Videos from Discovery Education (TM) (accessible via the Cambridge Learning Management System and supplied on the Teacher's Book DVD) provide new angles on a range of academic subjects.