In brief, the field of Instructional Design (ID) lies at the intersection of at least three disciplines: education (how people learn in formal and informal settings), psychology (how humans learn and develop), and communication (message design and communication). The field is not new; depending on the source you use, you can trace it back to the 1940s.
There are at least 40 different ID models (!) used in education, corporate, and government settings. All models share the same underlying process of Analysis, Design, Development, Implementation, and Evaluation, also known as the ADDIE process. This model was developed by Drs. Dick and Carey, who used to be faculty at the FSU College of Education. It is a world-recognized model, and I am proud that I was Dr. Dick’s student (a long time ago). There are other wonderful mentors and experts in the field (Marcy Driscoll, Bob Reiser, Walt Wager) which greatly contributed to my growth as instructional designer. Please access my diigo collection on ID.