The Secret Doctrine: the Synthesis of Science, Religion, and Philosophy, both volumes in a single file

According to Wikipedia: "Helena Petrovna Blavatsky (born as Helena von Hahn, 12 August, 1831, Yekaterinoslav, Yekaterinoslav, Russian Empire (today Dnipropetrovsk, Ukraine) – died 8 May 1891, London, Great Britain) was a founder of Theosophy and the Theosophical Society."