Experimental analysis and forecasting tools and techniques, developed by the research community, have been tested and evaluated during 2004 at the Tropical Prediction Center/National Hurricane Center (TPC/NHC), in real time for the fourth consecutive hurricane season, under the auspices of the U. S. Weather Research Program's Joint Hurricane Testbed (JHT). Nine initial JHT projects concluded in 2003. As a result of these activities, upgrades to the Geophysical Fluid Dynamics Laboratory (GFDL) hurricane model were implemented at the beginning of the 2003 season, and four other techniques have been accepted for operational implementation at TPC/NHC beginning in 2004. Among these are the analysis of tropical cyclone intensity via data from the Advanced Microwave Sounding Unit (AMSU), and the explicit consideration of upper ocean heat content in the Statistical Hurricane Intensity Prediction Scheme (SHIPS). A second round of 15 JHT projects began in 2003, and most of these will continue testing and evaluation through the 2005 season. The currently active projects include proposed upgrades to dynamical models and model components, enhancements to observed data and assimilation techniques, track forecasting algorithms, intensity estimation and forecasting algorithms, and assessments of dynamical model forecasts of tropical cyclogenesis and of tropical cyclone rainfall. Additionally, a third round of projects is expected to begin in spring 2005, with testing and evaluation to take place during the 2005-06 seasons. The complete life cycle of a JHT project will be summarized, including proposal submission and review, quasi-operational testing and evaluation, and decisions on operational implementation. Potential future opportunities for the involvement of additional members of the research community in the JHT will also be described.