Emma Tonkin looks at the current landscape of persistent identifiers, describes several current services, and examines the theoretical background behind their structure and use. <a href="/category/issue-number/issue56">issue56</a> July 2008 <a href="/category/article-type/feature-article">feature article</a> <a href="/taxonomy/term/809/author-info">emma tonkin</a> Brian Kelly reports on the WWW9 conference, held in Amsterdam, in May 2000. <a href="/issue24">issue24</a> June 2000 <a href="/category/article-type/tooled">tooled up</a> <a href="/taxonomy/term/203/author-info">brian kelly</a> William Y. Arms, D-Lib publisher and Amy Friedlander, the editor, describe this successful Web-based magazine that carries more technically-minded articles on all aspects of digital/electronic libraries research. <a href="/issue5">issue5</a> September 1996 <a href="/category/article-type/review">review</a> <a href="/taxonomy/term/271/author-info">amy friedlander</a>, <a href="/taxonomy/term/294/author-info">william y. arms</a>