Full Idea
Russell was the inventor of the naïve set theory so often attributed to Cantor.
Gist of Idea
Russell invented the naïve set theory usually attributed to Cantor
Source
report of Bertrand Russell (The Principles of Mathematics [1903]) by Shaughan Lavine - Understanding the Infinite I
Book Reference
Lavine,Shaughan: 'Understanding the Infinite' [Harvard 1994], p.3