This book discloses the relationship between climate and rice cropping systems in the Brahmaputra basin through statistical analysis and field survey. It is the first attempt to study Bangladesh and Assam in the Brahmaputra basin as a continuous ecological unit; Brahmaputra floodplain zone. The author found rice cropping systems in the Brahmaputra floodplain zone is historically changing to adapt to the ongoing climate changes in the basin. It means that by studying cropping systems in micro level, we can detect what kinds of climate change are occurring in the area. This is an attempt to provide an alternative methodology to understand the meso-scale climate change which climatologist could sometimes overlook.