This document describes a mentoring network for mid-career teachers--a natural extension beyond the induction stage. The focus for this presentation is the anatomy of change through colleague-led staff development. The noteworthy elements of this approach are as follows: (1) the voluntary participation of effective elementary and secondary teachers systematically assisting each other to fine tune their instructional skills; (2) formative evaluation exclusive of administrative involvement; (3) university/school district resources focused on teacher-initiated instructional change; (4) internal and external program support; and (5) a self-perpetuating change model empowering teachers in the district to expand and enhance their instructional competencies. (Author/JD)