On the fourfold root of the principle of sufficient reason, and On the will in nature

Schopenhauer, Arthur 1788-1860. On the fourfold root of the principle of sufficient reason, and On the will in nature / two essays by Arthur Schopenhauer ; translated by Mme. Karl Hillebrand . - Rev. ed. . - London : G. Bell and sons, 1910 . - xxviii, 380 p. ill. 19 cm. - (Bohn’s philosophical library )