This document, 10th in a series of 11 subvolumes of a handbook providing training for educational research and development personnel in the development of instructional materials, deals with the task of evaluating instructional materials. The document is organized according to the three sequential steps involved in performing the task. Step 1 is to conduct an information tryout of the instructional program and revise the program when necessary. Step 2 is to conduct a developmental tryout of the instructional program and revise the program when necessary. Step 3 is to conduct a field test of the instructional program. More specific substeps list the procedures for performing the steps. Background information covers (a) purposes of evaluation; (b) the cyclical nature of program tryout and revision; (c) four interrelated elements in the tryout and revision process; and (d) the amount of program material to schedule for tryout. (PD)