Theodor Lessing, Die verfluchte Kultur (published in German, 1921)
Albert Einstein, The Meaning of Relativity (1921)
Nicolai Hartmann, Grundzüge einer Metaphysik der Erkenntnis (published in German, 1921)
Franz Rosenzweig, The Star of Redemption (1921)
Ludwig Wittgenstein, Tractatus Logico-Philosophicus (First published in German in 1921 as Logisch-Philosophische Abhandlung; translated by C. K. Ogden with assistance from G. E. Moore, F. P. Ramsey, and Wittgenstein himself. G. E. Moore suggested the Latin title to pay homage to Tractatus Theologico-Politicus by Benedictus Spinoza. This book allegedly aimed to complete logical atomism as espoused by Bertrand Russell and G. E. Moore.)
Liang Shuming, The Civilization and Philosophy of the East and the West (1921)