The year 1995 marks the 90th anniversary of Einstein's first description of the theory of relativity. In this unique reference book, Einstein's multi-disciplinary contributions to science and society are presented in an easy-to-read dictionary format. The book is a synthesis of existing literature on Einstein including his own writings, biographies, and the secondary literature published during the past 40 years. The author presents all facets of Einstein's life, which began in Ulm, Germany, and came to an end in Princeton, New Jersey, spanning a tumultuous period marked by two world wars and the dawn of the atomic age. The year 1995 marks the 90th anniversary of Einstein's first description of the theory of relativity. In this unique reference book, Einstein's multi-disciplinary contributions to science and society are presented in an easy-to-read dictionary format. Einstein's personal life, physics, philosophy, and politics are covered in more than 600 entries. The book is a synthesis of existing literature on Einstein, including his own writings, biographies, and the secondary literature published during the past 40 years. The author presents all facets of Einstein's life, which began in Ulm, Germany, and came to an end in Princeton, New Jersey, spanning a tumultuous period marked by two world wars and the dawn of the atomic age. Abundant information is presented in a style that is accessible to students and non-scientists. Entries are cross-referenced for easy access to related information. The work also includes a chronological synopsis, a genealogical chart, and several appendices.