See also the updated 2006 edition in various formats at bahai.org and bahaiebooks.org.
Documents posted between 2003-2012 had various slightly different URLs and sometimes can be found in archive.org with addresses like bahai-library.com/file.php5?file=esslemont_bahaullah_new_era.
Documents posted prior to October 2003 were at bahai-library.org [archive.org] and had completely different URLs.