Russell
1.2.3.1 Photo
1.2.3.2 Background
1.2.3.3 Principia mathematica
1.2.3.3.1 Page from Principia
1.2.3.3.2 Comment on page
1.2.3.4 Russell's Paradox
1.2.3.5 Russell's Definition
1.2.3.6 The Logical School of Mathematics