The National Planning Association is preparing a series of studies on the Economics of Competitive Coexistence. The first three volumes in the series are: "Communist Economic Strategy: The Role of East-Central Europe," by Jan Wszelaki (132 p. $3.00); "Japan, China, and the West," by H. Michael Sapir (79 p. $2.00); and "East and West in India's Development," by Wilfred Malenbaum (67 p. $1.75).