by R. L. Dix and R. G. Beidleman (1969). Results of the first year of field data collection under this program were synthesized in a volume edited by N. R. French (1971). Development of the large-scale model constructed to depict the processes and the dynamics of state variables in grassland ecosystems was presented by Innis (1978). Soon to appear will be two volumes integrating studies of American grasslands with IBP studies in other grasslands of the world (Coupland, in press) and the application of systems analysis to understanding grassland function and utilization (Breymeyer and Van Dyne, in press). The present volume presents current results and comparisons of field investigations and experimental studies that were conducted under this program.