In the early 1980s a large workshop was organized by David Atlas and Otto Thiele at NASA Goddard (GSFC) to explore the opportunities for measuring rain rates from spaceborne sensors. Soon after (late summer, 1984) several small meetings took place at GSFC to plan and propose such a mission. Some one-page white papers were drawn up mainly based on a concept by Thomas T. Wilheit (low Earth orbiter in tropical inclination, passive and active microwave radiometers, possible use of an on-the-shelf ESMR). Much activity was generated from a call from NASA HQ for a low cost atmospheric mission. Eventually, a competition was held at NASA HQ involving 17 participants. TRMM won the contest and plans were begun for a Phase A study at GSFC with Gerald North as Study Scientist. International partnerships were sought and agreements were met with the Japanese Space Agency and preliminary negotiations began. During this period Director of the Laboratory for Atmospheric Sciences, Marvin Geller, suggested Eugene Rasmussen to be Chair of a Science Advisory Committee to spell out science requirements and opportunities for such a mission. The prestige and winning personality of Eugene Rasmussen were key to the early acceptance of TRMM by the science community as well as by the decision makers in Washington and Tokyo. Another milestone was reached when Joanne Simpson was installed as the first Project Scientist. Many trips to Japan ensued with Rasmussen's committee, members from NASA HQ, key scientists and project engineers. TRMM was launched from a Japanese site using the Japanese H2 rocket in November, 1997, and has been flying ever since. Christian Kummerow was the next Project Scientist as the mission became operational. TRMM had a near-death experience when NASA pondered whether the mission should be terminated in 2005, because of the on-board fuel necessary for a safe oceanic re-entry. The mission was saved mainly through the courageous efforts of Robert Adler, then Project Scientist. The TRMM program has been a striking success leading to many more applications than the founders ever expected. Many lives have no doubt been saved and we have learned much about tropical rain, the general circulation of the atmosphere-ocean system and its many peculiarities such as ENSO.