Good luck with your studies! Rapid Application Development (RAD) is the idea, as the name implies, of quickly building and completing software projects. In the real world, the requirements are always changing based on business input. With the RAD approach, you work at getting the end users and the developers together through the development cycle so you spiral in to the solution. It's not so much a formal design methodology as a common sense approach to how most shops end up developing software anyway.
The bible, in my opinion, on RAD development is the book Rapid Development by Steve McConnell. Steve's book is how most of us in the software business figured out how to manage!
This was first published in February 2002