This document discusses Glickman's theory of developmental supervision, which views supervision as a process aimed at improving instruction. The theory proposes that teachers operate at different levels of professional development and effectiveness, so they need to be supervised in different ways. The goal of supervision is to help every teacher progress to higher stages of thought. The supervisor's task involves three phases - diagnostic, tactical, and strategic. In the diagnostic phase, the supervisor assesses teachers. In the tactical phase, the supervisor helps teachers solve immediate problems using directive, collaborative, or nondirective approaches. In the strategic phase, the supervisor aims to accelerate teacher development by exposing them to new ideas and problem-solving techniques.