The view discussed is that mathematics teachers are becoming a rare, if not endangered, species, and the public image of mathematics needs to be changed. The mathematics teacher is termed the crucial variable, and a need is seen for changes in mathematics teacher education. The approach described is based on the following assumptions: (1) mathematics teachers must know mathematics well beyond the level they may be expected to teach; (2) mathematics teachers need specialized knowledge; (3) teacher education is the key to educational reform; (4) teachers must be prepared for the realities and contingencies of teaching; and (5) teacher education is an on-going, developmental process. The material strives to: (1) present a broad overview of developments in mathematics teacher education as a perspective from which to view the current situation; (2) propose a taxonomy for teacher education; (3) illustrate the taxonomy and expand upon it through selected examples; (4) describe the operation of a teacher education program based on the taxonomy; (5) relate the taxonomy to the on-going, developmental nature of teacher education; (6) suggest content and experiences for inclusion in teacher education; (7) offer a model for program design; and (8) report preliminary experiences and evaluation. (MP)