Abstract: This paper central claim is that there is a need for microscopic Instructional design, which appears to mean the detailed modeling and design of specific components and adaptations for teaching specific material. It will discuss the microscopic instructional planning in the context of E-learning. So it will be concentrated in the design of the last level of E-learning system (the didactic activity). The learning activity, which is regarded as a complex object, must be seen with a microscopic approach where all its components are manifested. The pedagogical instruments constitute its primary matter where theirs molecules are the smallest collection of its components, which retains the properties of that material (according to the teaching intention). The instructional designer must do several projection for each pedagogical instrument to be realized by other actors (pedagogical and didactic model, cognitive model, knowledge objects model and interface model).