On his mother's side, <answer>Hayek</answer> was second cousin to the philosopher Ludwig Wittgenstein. His mother often played with Wittgenstein's sisters, and had known Ludwig well. As a result of their family relationship, <answer>Hayek</answer> became one of the first to read Wittgenstein's Tractatus Logico-Philosophicus when the book was published in its original German edition in 1921. Although <answer>Hayek</answer> met Wittgenstein on only a few occasions, <answer>Hayek</answer> said that Wittgenstein's philosophy and methods of analysis had a profound influence on his own life and thought. In his later years, <answer>Hayek</answer> recalled a discussion of philosophy with Wittgenstein, when both were officers during World War I. After Wittgenstein's death, <answer>Hayek</answer> had intended to write a biography of Wittgenstein and worked on collecting family materials; and he later assisted biographers of Wittgenstein.
Who was among the first readers of Ludwig  Wittgenstein's book?
Hayek