The concentric approach is a method for organizing subject matter over multiple years of study where a topic is introduced at a basic level in early grades and then explored in more depth and complexity in later grades. It aims to provide repeated exposure to topics in a way that gradually builds students' understanding from simple to more sophisticated. The key aspects are introducing topics as wholes first before analyzing parts, spreading content over several years with increasing difficulty, and allowing for revision of previously taught material. While it provides a framework and considers students' developmental levels, it requires capable teachers to maintain novelty and interest across years of teaching.