An international field campaign CINDY/DYNAMO took place in the Indian Ocean and its surrounding regions during October 2011-March 2012. The main goal of the field campaign was to collect observations that are needed for advancing our understanding and forecast of MJO initiation over the Indian Ocean. Three scientific hypotheses on interaction between convection and its environmental moisture, evolution in cloud population, and air-sea interaction were proposed to guide the design and operation of the field campaign. Unprecedented data were collected by numerous instruments of advanced technology from ground, airplanes, ships, moorings and other platform. These data cover detailed processes through all stages of convective initiation of three very different MJO events. Field observations were released for public use one year after the completion of the field campaign. Studies using these observations have increasingly emerged. These studies confirmed some existing knowledge, challenge some well-accepted paradigms, and reveal new phenomena that motivate novel thinking and approaches to solve the puzzle of MJO initiation.