The document is the third of a five-part series focusing in minute detail on the processes involved in the formulation of an instructional systems development (ISD) program for military interservice training that will adequately train individuals to do a particular job. The Develop phase consists of inputs, procedures, and outputs presented for five steps. The first step, Specify Learning Events/Activities, focuses on the classification of learning objectives by learning category in order to identify learning guidelines necessary for optimum learning to take place. The second step, Specify Instructional Management Plan and Delivery System, focuses on media selection to determine the manner in which instruction is to be packaged and presented to the student. Instructional management plans are developed to allocate and manage all resources for conducting instruction. The third step, Review/Select Existing Materials, focuses on the evaluation of materials for their appropriateness to the learning objectives, learner characteristics, and selected learning guidelines and management plan. The fourth step, Develop Instruction, assists the instructional designer in using available resources to produce instructional materials. The final development phase is Validate Materials, to ensure that instructional works and students achieve the learning objectives. A list of references, glossary, and index is included. (Author/EC)