Jacob Klein (March 3, 1899 – July 16, 1978) was a Russian-American philosopher and interpreter of Plato, who worked extensively on the nature and historical origin of modern symbolic mathematics.
A student of Nicolai Hartmann, Martin Heidegger, and Edmund Husserl, he later taught at St. John's College in Annapolis, Maryland from 1938 until his death.
Of Klein's first book Greek Mathematical Thought and the Origin of Algebra, Strauss said: The work is much more than a historical study.
[2]Russian born French philosopher Alexandre Kojève counted Klein as one of the two people (along with Strauss) from whom he could learn anything.
[3] The central thesis of his work Greek Mathematical Thought and the Origin of Algebra is that the modern concept of mathematics is based on the symbolic interpretation of the Greek concept of number (arithmos).