MDSplus is a data acquisition and analysis system used worldwide predominantly in the fusion research community. It was based on the original system called MDS which was created in 1982 at the Plasma Science and Fusion center at MIT. Development of MDSplus began in 1987 by a collaboration of software developers who were charged with providing a data acquisition system for three new fusion experiments under construction: CMOD at MIT, ZTH at LANL and RFX at Padova, Italy. The design of MDSplus combined the functionality of MDS with new features suggested by the developers from the other laboratories. The development of MDSplus used a RAD (rapid application development) approach before RAD became a mainstream methodology. MDSplus was implemented and ready for the initial operation of CMOD in 1991. Since that time, many other fusion facilities adopted MDSplus for data acquisition and/or for exporting their data to other sites. Today MDSplus is used around the world for fusion energy research, space exploration and other fields of science and technology. Work on MDSplus continues to enhance its capabilities, support more platforms, and improve its reliability. It is anticipated that MDSplus will continue to provide valuable tools for the fusion energy research community. This paper provides a brief introduction to MDSplus and discusses the history of its design and development.