Who is Bertrand Russell from The Problems of Philosophy and what is their importance?

Bertrand Arthur William Russell (1872-1970) was one of the most important philosophers of the 20th century. He was a British philosopher, social critic, and logician. His most important philosophical work was in logic and analytical logic. He is well-known for his assertion that mathematics is reducible to logic, his philosophy of language (particularly his theory of definite descriptions) and logical atomism.