He is currently the Sidney Hellman Ehrman Professor of History Emeritus at the University of California, Berkeley.

In 1971, he completed his Doctor of Philosophy degree in history at Harvard University under the tutelage of H. Stuart Hughes.

His dissertation was later revised into the book The Dialectical Imagination, which covers the history of the Frankfurt School from 1923 to 1950.

While he was conducting research for his dissertation, he established a correspondence and friendship with many Frankfurt School members.

[citation needed] In 2023, he published a sequel to The Dialectical Imagination on the contemporary turns in Critical Theory, entitled Immanent Critiques: The Frankfurt School Under Pressure.