Dynamics of Potassium in Paddy Soils is an exciting new book for all those concerned with rice (Oryza sativa/japonica). Response of rice (T. aman and Boro) to potassium (K) application was studied under pot and field conditions with different levels of K. Soil solutions and rain, and irrigation waters were analyzed for K. Terrace soils released more K than Old Brahmaputra floodplain soils. The Q/I relationship showed that the equilibrium exchangeable K (EK0) and labile K (KL) of terrace soil were higher than floodplain soils. The potential buffering capacity (PBCK) was higher in floodplain soil. Soil solution K and exchangeable K increased due to alternately flooding and drying over continuously flooded soils. The exchangeable K increased with added K but decreased with time. Rice grown under pot and field conditions responded positively to K in K deficient soils. Considering the MBCR and net marginal return 60 and 90 kg K ha-1 was found economically viable for rice. The balance of K was negative irrespective of soils and seasons. The negative K balance reduced to some extent with added K in K deficient soils.