This is a volume of papers organized by Professor Leontief for the 1976 meeting of the Economics section of the British Association for the Advancement of Science. After a paper by Professor Leontief applying input-output to the future of the world economy, other papers consider prices, regional problems, material supplies, urban problems, technical progress, unemployment and energy policy. There are two papers with a broader view of the British economy, one surveying government policy on the industrial structure of the economy and one considering the use of input-output for monitoring the development of the economy.