Central Themes, Level Three, General and Life Sciences (GLS), is an English language course book designed for GLS students in Secondary Three. Its scope and sequence is based on the English syllabus of the Lebanese Ministry of Education and Higher Education.

Central Themes, Level Three, GLS, presents topics, such as technology, teenagers, natural phenomena, human rights, environment, and hygiene and nutrition, which exhibit universality and stand true for people of all cultures. Through those topics, students better understand human experiences and gain insight into how the world works.

Central Themes, Level Three, GLS, is ideal for classroom interaction and test preparation.