title_body: Is the  still needed in ePub 3? Suprised I haven't found this when searching the site under the parameters &lt;guide&gt; and when searching IDPF documentation for ePub 3 spec I didn't see an answer.  I was curious what does the &lt;guide&gt; do at the end of the OPF file in an ePub 3?  I did read the write up "Where do you start an ePUB and what is the  section of the .OPF file?" but this was published back in 2011 when ePub 2 was still common: 
  
  
    “The guide element identifies fundamental structural components of
    the publication, to enable Reading Systems to provide convenient
    access to them.” So how does the  work? Essentially, it points
    to where particular pieces of the book can be found, allowing reading
    systems to go directly to that file or location.
  
  
  For example:
  
      &lt;guide&gt;
          &lt;reference href="foo.xhtml" type="cover" title="Cover"/&gt;
          &lt;reference href="bar.xhtml" type="text" title="Start"/&gt;
      &lt;/guide&gt;
  &lt;/package&gt;
  
  
  I know traditionally ePub2 used the &lt;guide&gt; often and per Apple documentation I use &lt;guide&gt; in fixed layout but other then that is there still a need for the &lt;guide&gt; or is it only for legacy devices and reading engines?
upvoted_answer: It's now deprecated in epub3 in favor of the landmark NAV element. 
  http://www.idpf.org/epub/301/spec/epub-publications.html#sec-guide-elem
  
  Because support for NAV is pretty much universal in reading systems, I see no reason why to include it now.