This is the most comprehensive survey of the mathematical life of the legendary Paul Erdös, one of the most versatile and prolific mathematicians of our time. For the first time, all the main areas of Erdös' research are covered in a single project. Because of overwhelming response from the mathematical community, the project now occupies over 900 pages, arranged into two volumes. These volumes contain both high level research articles as well as "key" articles which survey some of the cornerstones of Erdös' work, each written by a leading world specialist in the field. A special chapter "Early Days", rare photographs, and art related to Erdös complement this striking collection. A unique contribution is the bibliography on Erdös' publications: the most comprehensive ever published.