From Vilna the Baran family moved to Berlin, and then, in 1925 back to Moscow, but Paul stayed in Germany to finish his secondary school.

During these years in Germany, he met Rudolf Hilferding, author of Finance Capital and wrote under the pen name of Alexander Gabriel for the German Social Democratic Party journal Die Gesellschaft.

He worked under John Kenneth Galbraith at the Strategic Bombing Survey traveling to post-war Germany and Japan.

[3] From 1949, he was an active participant in the formulation of editorial ideas and opinions in Monthly Review magazine edited by Paul Sweezy and Leo Huberman.

Baran introduced the concept of "economic surplus" to deal with novel complexities raised by the dominance of monopoly capital.

[5] Monthly Review has recently published a book of correspondence between Sweezy and Baran, which illuminates the development of their ideas on political economy, and in particular, their collaboration in writing their seminal work, Monopoly Capital.

Potential economic surplus," in contrast, is "the difference between that output that could be produced in a given natural and technical environment with the help of employable productive resources, and what might be regarded as essential consumption."

This was defined as "the difference between society's 'optimum' output available in a historically given natural and technological environment under conditions of planned 'optimal' utilization of all available productive resources, and some chosen 'optimal' volume of consumption.