Physics Department, Montana State University, Bozeman, MT 59717-3840

HESSI will depend on other spacecraft and ground-based observatories (GBOs) for observations of the thermodynamic and magnetic context of particle acceleration and explosive energy release in solar flares. The definition of plans for scheduled campaigns and targets of opportunity by space missions and GBOs will be coordinated through the Max Millennium Program. An outline of the Max Millennium program is on the WWW at http://solar.physics.montana.edu/max\_millennium/. Although HESSI views the whole Sun, many space and GBO instruments have limited fields of view. In order to put together a compelling dataset, it is better to have comprehensive observations of some flares than isolated observations of many flares. Experience shows that the effectiveness of coordinated observations depends on:

• Definition of campaigns and targets of opportunity
• Evaluation of current solar conditions
• Definition and communication of plans and targets
• Access to GBO and spacecraft data archives
• Coordinated Data Analysis Workshops

During the coming year the emphasis of the Max Millennium program will be on the development and testing of these capabilities.