Introduction to Supersymmetry
Abstract: Supersymmetry is a remarkable subject that has fascinated particle physicists since it was originally introduced. Although supersymmetry is no longer a new idea, we still do not know in what form, if any, it plays a role in the proper description of nature.
The present status of supersymmetry might be compared very roughly to the status of non-Abelian gauge theories twenty years ago. It is a fascinating mathematical structure, and a reasonable extension of current ideas, but plagued with phenomenological difficulties. (link to pdf)