In a method and computer-implemented system of modular instruction a body of knowledge is divided into cognitive constructs, with instructional materials and post-instruction assessments being associated with each of the cognitive constructs and comprising a learning packet. The instructional material associated with each learning packet is presented to a student, followed by the post-instruction assessment associated with each learning packet. A result of the post-instruction assessment is compared to a pre-defined standard for that learning packet to determine whether the instructional material associated with another learning packet should be presented to the student, or if the instructional material associated with the current learning packet should be presented again to the student. The learning packets can be presented in default sequence or they can be reordered and presented in a user-selected sequence, and all or only a portion of the learning packets can be presented to the student.