This collection contains contributions from researchers in three broad areas: capital-investment theory; development and welfare economics; and issues related to capitalism and socialism. Some of the contributions are expository, providing an overview of what has been achieved in the relevant literature to date. These are accessible to non-specialists and graduate students alike. Other chapters are aimed primarily at researchers and attempt new interpretations and explore new directions. Some of the specific topics covered are "old" versus "new" growth theories, sensitivity analysis in dynamic optimization models, efficiency wage theories, cost benefit analysis, reform of market socialism and optimal redistribution.