Ludwig Lachmann took a strong interest in the history of economic thought, particularly as it pertained to methodology. While he would not have claimed to be an Austrian in the Misesian tradition, his writings have influenced Austrians. Here is his study of the methodological and political legacy of Max Weber, who himself influenced Mises's own methodological perspective. Lachmann zeros in on Weber's understanding of the role of institutions in society.
German economist who became a member of and important contributor to the Austrian School of economics. He grew to believe that the Austrian School had deviated from Carl Menger's original vision of an entirely subjective economics. To Lachmann, Austrian Theory was to be characterized as an evolutionary, or "genetic-causal", approach against the equilibrium and perfect knowledge found in mainstream Neoclassical economics. Lachmann's "fundamentalist Austrianism" was rare—few living Austrian economists saw their work as departing from the mainstream. He underscored what he viewed as distinctive from that mainstream: economic subjectivism, imperfect knowledge, the heterogeneity of capital, the business cycle, methodological individualism, alternative cost and "market process". His brand of Austrianism now forms the basis for the "radical subjectivist" strand of Austrian Economics. His work was highly influential upon later, American developments of the Austrian School. He was also a strong advocate of using hermeneutic methods in the study of economic phenomena.
Interesting early take on how aspects of Weber (theory of institutions) could be distilled from the hints that he gave in his voluminous writings. While a worthy endeavour, Lachmann's idea of 'the plan' as the key to understanding Weber's idea of action and institutions (structure) is not wholly convincing. I think habitual action is a much more convincing way of understanding the connections between action and structure.