This publication was designed as an aid to reinforcing and improving teachers' diagnostic/prescriptive capabilities. The main section examines characteristics of reading diagnosis and describes informal diagnostic techniques (including teacher observation, informal reading inventories, and the cloze procedure) and formal diagnostic techniques (including standardized tests and visual screening tests). Sample forms are provided to demonstrate the use of the cloze technique and observational techniques. Other sections of the publication discuss the concept of diagnostic/prescriptive reading instruction, show how prescriptions are developed, and explain how diagnostic/prescriptive reading instruction is evaluated. Strategies for presenting the material to workshop participants are listed for each section. (GW)