PRINCIPIA MATHEMATICA. BY. ALFRED NORTH WHITEHEAD. AND. BERTRAND RUSSELL, F.R.S.. VOLUME I. SECOND EDITION
https://lesharmoniesdelesprit.files.wordpress.com/2015/11/whiteheadrussell-principiamathematicavolumei.pdf 22.2 MB PDF
"Alfred North Whitehead (1861–1947) was a British mathematician and philosopher best known for his work in mathematical logic and the philosophy of science. In collaboration with Bertrand Russell, he co-authored the landmark three-volume Principia Mathematica (1910, 1912, 1913). Later, he was instrumental in pioneering the approach to metaphysics now known as process philosophy."